Improved vibrating sample device and related magnetometer system

Abstract

The invention refers to a device (10) for a magnetometer system (50) comprising a sample carrier (14) with a first sample receiving portion (13a) and a second sample receiving portion (13b), the first and second sample receiving portions (13a, 13b) being movable with respect to each other. A driving system (20) of the device (10) is configured for driving a reciprocating movement of the first and second sample receiving portions (13a, 13b) such that the first and second sample receiving portions (13a, 13b) move antiphasically with respect to each other. A first detection element (12a) and a second detection element (12b) are configured and arranged with respect to the sample carrier (14), such that, during a reciprocating movement of the first and second sample receiving portions (13a, 13b) with respect to each other driven by the driving system (20), variations in a magnetic field caused by the moving first and second sample receiving portions (13a, 13b) induce mutually cancelling electric currents and / or voltages upon the first and second detection elements (12a, 12b). The invention further refers to a magnetometer system (50) comprising such device and to a related method of obtaining an output signal corresponding to a magnetization of a test sample (32).

Description

[0001] Improved vibrating sample device and related magnetometer system

[0002] FIELD OF THE INVENTION

[0003] The present invention is in the field of measuring devices and complements thereof and refers in particular to a new type of device usable in a magnetometer system and to a magnetometer system including such device as well as to a related method.

[0004] BACKGROUND OF THE INVENTION

[0005] Devices usable to measure gradient fields are known in the art. One exemplary use of such a device is in a magnetometer system, which is a measuring system for measuring a magnetization of a sample, typically a solid-state sample. A magnet, for example an electromagnet, may be used to generate a known external magnetic field and the resulting magnetization in the sample is measured.

[0006] During the measurement, different parameters may be varied to explore the dependence of magnetization of the sample upon those parameters. A typical parameter to be explored through such variations is temperature. Temperature variations may allow investigating temperature dependent magnetic properties of the sample, including magnetic phase transitions.

[0007] Cryostat systems are available in most laboratories to allow the measurement of different physical properties, such as magnetization, under controlled temperature conditions, including temperature values that may range from ambient temperature to close to absolute zero-point temperature. Such cryostat systems typically make use of superconducting electromagnets that are able to generate very strong magnetic fields. The use of such cryostat systems may allow exploring broad ranges of temperatures and magnetic field densities, for example for Hall effect measurements.

[0008] The magnetic induction law relates an electric current induced in a coil with an inducing magnetic field: wherein is a time- varying magnetic flux and U(t) is an electric voltage induced in a coil. The magnetic flux generated by a magnetic field B through a coil wound around an area A is defined as:

[0009] Thereby, the magnetic field can be considered as a magnetic field generated by a magnetic dipole m: 4711 wherein r(t) is a vector defined between a position of the magnetic dipole and the position in space at which the magnetic field is measured. As a result of the above equations, when the position of a magnetic dipole, for example of a magnetized sample, varies in space, an electric voltage may be induced in a coil arranged nearby. If such spatial variation is periodic, an induced periodic variable electric current, with time-varying electric voltage, may be measurable in the coil.

[0010] Known magnetometer devices make use of the above physical laws to provide direct measurements of the magnetization of a sample. A spatial variation of the sample with respect to a measurement coil is detected as a variation in electrical voltage or current and correlated with a magnetization of the sample. Some known examples of such magnetometer devices are vibrating sample magnetometers (VSM), vibrating coil magnetometers and SQUID-magnetometers. A VSM uses a first-grade gradiometer device comprising two stationary coils wound in opposite directions, with respect to which a sample is made to vibrate. In a vibrating coil magnetometer, instead the coils are made to vibrate. SQUID-magnetometers typically use higher-order gradiometer devices and more complex detection electronics.

[0011] The possibility of optimizing the geometry of a device for use in a magnetometer, in particular of a gradiometer device, has been discussed in the literature. As a consequence of the above equations showing the induction law, the measurable electric voltage is proportional to the time variation of the magnetic field, and hence increase with increasing amplitude and / or frequency of the positional oscillations of the magnetic sample, the movement of which induces the measurable electric signal. Therefore, it is interesting to obtain sample oscillations with amplitude and frequency as large as possible.

[0012] A further aspect is the necessity of avoiding interferences in the form of contributions to the measurable electric signal that are not induced by the sample itself but by other elements, in particular by a sample carrier on which the sample may be arranged. Even diamagnetic sample carriers generate a distorting contribution to the measurable electric signal that may increase noise and reduce the quality and reliability of the measurement.

[0013] The distortion caused by the sample carrier may be particularly significant in the case of thin- layer samples, which may have a thickness several orders of magnitude smaller than a thickness of a sample carrier (a substrate) on which the sample is arranged.

[0014] Thus, there is room for technical improvement in the field of devices usable in a magnetometer system, in particular in terms of reducing distortions upon the measurement signal.

[0015] SUMMARY OF THE INVENTION

[0016] One aim of the present invention is providing a device usable in a magnetometer system allowing measurements of a magnetically induced measurement signal with improved signal to noise ratio and with reduced distortions, thereby overcoming the previously mentioned disadvantages of the prior art. This is achieved by a device according to claim 1 and by a magnetometer system according to claim 12 and by a method according to claim 15. Preferable embodiments of the invention are defined in the appended dependent claims. The first aspect of the invention refers to a device for a magnetometer, which device may preferably be a gradiometer device, in particular a first-grade gradiometer device. The device of the invention comprises a sample carrier comprising a first sample receiving portion and a second sample receiving portion. The first sample receiving portion is configured for receiving thereon a first sample carrier element, for example a first sample receiving substrate, and the second sample receiving portion is configured for receiving thereon a second sample carrier element, for example a second sample receiving substrate, which may preferably be identical to the first sample carrier element. Being configured for receiving thereon a first or second sample carrier element may in particular comprise having sufficient room and being designed for receiving the corresponding sample carrier element and / or having appropriate receiving elements for receiving and possibly fixating a sample carrier element, for example a fixation mechanism, an adhesive element or the like.

[0017] The sample carrier may have an elongated shape. The sample carrier may hence have a longitudinal dimension considerably greater than a width dimension and / or much greater than a thickness dimension thereof, the width dimension and the thickness dimension being mutually perpendicular and perpendicular to the longitudinal dimension. For example, typical dimensions of a sample carrier according to the invention may be a length of too cm to 600 cm , for example 300 cm, a width of 0,1 cm to 5 cm, for example 0.5 cm and a thickness of 0,01 mm to 1 cm, for example of 0.1 mm. The sample carrier may be configured such that the first sample receiving portion and the second sample receiving portion extend in parallel and in front of each other at least portionwise.

[0018] According to the invention, the first sample receiving portion and the second sample receiving portion are movable with respect to each other, preferably in parallel and in front of each other.

[0019] The mobility of the first and second sample receiving portions may be substantially limited to one single dimension or direction, which may in particular correspond to a longitudinal direction of the sample carrier, i.e., to a direction corresponding to the previously mentioned longitudinal dimension of the sample carrier. The device of the invention further comprises a driving system configured for driving a reciprocating movement of the first and second sample receiving portions such that the first sample receiving portion and the second sample receiving portion move antiphasically with respect to each other, preferably in parallel and / or in front of each other. “In front of each other” may refer herein, in particular, to a zero or origin-position around which each of the first and second sample receiving portions may respectively move, meaning that a position around which the first sample receiving portion reciprocatingly moves may be arranged in front of a position around which the second sample receiving portion reciprocatingly moves. “In front of each other” may alternatively or additionally imply that a range of motion of the first sample receiving portion may be arranged in front of a range of motion of the second sample receiving portion, such that both ranges of motion may overlap at least partly, possibly fully.

[0020] The driving system may generate a motion that makes the sample carrier move such that the first and second sample receiving portions are shifted back-and-forth, in particular along the previously mentioned direction in which the first and second sample receiving portions may be movable, for example along the longitudinal direction of the sample carrier, in a coordinated manner, such that the first sample receiving portion and the second sample receiving portion move alternatingly with a phase difference of 180°, in particular around the respective zeroposition. For example, thinking of a back-and-forth movement of the first and second sample receiving portions, a forward movement period of the first sample receiving portion may exactly correspond to a backward movement period of the second sample receiving portion and vice versa and the return points of the movement of the first sample receiving portion may timely coincide with the return points of the movement of the second sample receiving portion. As a consequence, the driving system can make the first and second sample receiving portions move back and forth alternatingly, possibly in parallel and / or in front of each other. The device according to the invention further comprises a first detection element and a second detection element. Each of the first and second detection elements may comprise a coil and / or a Hall sensor. The first and second detection elements are configured and arranged with respect to the sample carrier, such that, during a reciprocating movement of the first and second sample receiving portions with respect to each other driven by the driving system, variations in a magnetic field caused by the moving first and second sample receiving portions induce mutually cancelling electric currents upon the first and second detection elements. Said magnetic field may in particular be a surrounding magnetic field, possibly a constant and / or homogeneous magnetic field, in which the device, in particular the first and second sample receiving portions, may be arranged. Both the first detection element and the second detection element are suitable to receive an induced electric current as a reaction to a varying magnetic field in an environment thereof. In the presence of such external magnetic field, a movement of the first and second detection elements locally modifies the values of the surrounding external magnetic field and this leads to the induction of electric currents in the first and second detection elements. The arrangement and configuration of the first and second detection elements is such that these induced electric currents may mutually cancel off, i.e. may have substantially the same magnitude or amplitude but opposed sign. For example, if a first electric current II or a first electric voltage Vi is induced upon the first detection element, a second electric current I2 or a second electric voltage V2 simultaneously induced upon the second detection element may be l2=-Ii and V2=-Vi, respectively.

[0021] The first sample receiving portion and the second sample receiving portion may be movable with respect to the first and second detection elements.

[0022] When reciprocatingly moving driven by the driving system, the first sample receiving portion and the second sample receiving portion will generate opposed induced currents and / or voltages in the first detection element and the second detection element. If the first and second detection elements are or comprise coils, this may be implemented by the first and second detection elements comprising coils being coiled in opposite directions. For example if a coil corresponding to the first detection element is coiled clockwise, a coil corresponding to the second detection element is coiled counterclockwise or vice versa. As a result, a first electric voltage induced by the moving sample carrier portions in the first coil may substantially cancel off with a second electric voltage induced in the second coil by the moving sample carrier portions. However, this cancellation of contributions due to the symmetry of the system does not per se remove distortions that may be caused by one sample carrier element or substrate that may be attached to one of the sample carrier portions, for example between the sample carrier portion and a test sample to be measured, which may be arranged or deposited on a sample carrier element. For example, the test sample may be a thin-layer sample deposited on a considerably thicker sample receiving element or substrate that is attached to the sample carrier in one of the first and second sample receiving portions. Due to the configuration of the first and second sample receiving portions, the device according to the present invention allows receiving a second sample receiving element or substrate on the other one of the first and second sample receiving portions, which may possibly be identical to the first sample receiving element or substrate on which the test sample to be measured is received, and which may hence substantially cancel off also a distorting contribution of the first sample receiving element or substrate, in particular during the reciprocating movement, such that a net contribution measured by the first and second measuring elements may correspond to the test sample alone and not to the first and / or second sample carrier elements.

[0023] Thereby, the device according to the present invention allows achieving a measurement signal corresponding to a property of the test sample to be measured derived from the electric currents or voltages induced by a moving sample upon the first and second detection elements, in particular from a difference between both currents or voltages, with increased signal-to- noise ratio and hence better measurement accuracy.

[0024] The sample carrier is preferably configured such that the first and second detection elements are symmetrically configured and / or arranged with respect to the first and second sample receiving portions of the sample carrier.

[0025] According to preferred embodiments of the invention, the sample carrier may comprise a flexible continuous band, wherein the first and second sample receiving portions may be different portions of the band. A band may refer herein to a materially connected stripe having an elongated shape, i.e., an extension in a longitudinal dimension that is greater than a width of the band and much greater than a thickness of the band. "Flexible" may refer herein to the ability of the band of defining turns and / or corners deviating from a straight shape or direction, possibly using guiding elements such as rolling elements, pulleys or the like, such that different portions of the band along a longitudinal extension thereof may be angled with respect to each other. This may allow fitting the device of the invention to a desired geometry, for example with respect to a cryostat in which the device is to be introduced. Despite being flexible in this sense, the band may be substantially non-stretchable in the longitudinal direction. The band allows flexible configurations in terms of what trajectory in space is defined for the sample carrier, while a moving mass of the sample carrier, in particular of movable parts thereof that move in a reciprocating movement driven by the driving system, can be reduced with respect to previously known configurations of related devices making use of other types of sample carrier, in particular of rigid sample carriers made of plastic or quartz.

[0026] The band maybe made of a material being or comprising a plastic, Kapton, nylon, polyester or a combination thereof. According to preferred embodiments, the device of the invention may comprise one or more primary guiding elements, preferably one or more rolling elements or pulleys, for guiding a trajectory in space of the band-like sample carrier. The first sample receiving portion and the second sample receiving portion may be separated by the one or more primary guiding elements. The first sample receiving portion and the second sample receiving portion may preferably movably extend in parallel and in front of each other on different sides of the one or more primary guiding elements. The band maybe turned around, e.g., define a U-turn, around the one or more primary guiding elements, for example around a pulley, thereby defining two parallel and opposed sections of the band extending on either side of the pulley, with one of said sections comprising the first sample receiving portion and the other of said section comprising the second sample receiving portion. Notably, the one or more primary guiding elements may comprise more than one of such rolling elements or pulleys. The driving system may drive a reciprocating movement of the two sections of the band, for example by being connected to one or both of them, to drive a reciprocating movement of the first and second sample receiving portions against one or more pulleys, thereby making the first and second sample receiving portions move, in a reciprocating movement, in parallel and in front of each other, in particular with respect to the first and second detection elements, possibly in parallel. Thereby, the primary guiding elements, for example said one or more pulleys, may alternatingly rotate clockwise and anticlockwise with the alternating movement of the band in contact with it.

[0027] In preferred embodiments, the device of the invention with a band-like sample carrier, may further comprise one or more secondary guiding elements, preferably one or more rolling elements or pulleys, for guiding a trajectory in space of the sample carrier. Different portions of the sample carrier may be respectively separated by one of the one or more secondary guiding elements and may be preferably angled with respect to each other, for example by 450or 90°. The flexibility of the band-like sample carrier allows using such secondary guiding elements to adapt the trajectory in space of the sample carrier to a desired geometry, whence a direction in which the first and second sample receiving portions move reciprocatingly needs not correspond to a direction in which the reciprocating movement is originally generated by the driving system and may be adapted at will. For example, a direction in which the first and second sample receiving portions move reciprocatingly may be perpendicular to a direction in which the driving system generates the reciprocating movement.

[0028] While the previously described embodiments refer to a sample carrier comprising a flexible continuous band with the first and second sample receiving portions being different portions of the band, the principles of the present invention may also be implemented using a multipiece, in particular a two-piece, sample carrier, not necessarily band -like and / or flexible, even possibly rigid, with the first sample receiving portion and the second sample receiving portion being materially disconnected from each other, in particular due to their being formed in materially disconnected sections or elements of the sample carrier. In such configurations, the driving force generated by the driving system for driving the reciprocating movement of the first and second sample receiving portions may be independently transmitted to each of the sections of the sample carrier respectively containing the first and second sample receiving portion.

[0029] According to preferred embodiments, the device of the invention may further comprise at least a tensioning element configured for tensioning the sample carrier. The at least one tensioning element may be preferably connected to a longitudinal end of the sample carrier and / or to a longitudinal end of a respective portion of the sample carrier comprising one of the first or second sample receiving portion. The at least one tensioning element, which may for example comprise at least one biasing element, like e.g., a spring, may keep the sample carrier tensioned during a reciprocating movement driven by the driving system. The at least one tensioning element may further compensate thermally induced variations in an extension of the sample carrier in the longitudinal direction and may maintain a constant voltage of the sample carrier in the longitudinal direction despite such thermally induced variations. In configurations in which the first and second sample receiving portions may be materially disconnected from each other, each of the sections of the sample carrier respectively comprising one of the first and second sample receiving portions may be tensioned by a respective tensioning element, which may in particular be connected to a longitudinal end of the corresponding section of the sample carrier, for example at a longitudinal end opposed to a respective longitudinal end connected to the driving system. In configurations in which the first and second sample receiving portions may be different portions of a band-like sample carrier, one longitudinal end of the sample carrier, in a section of the sample carrier comprising for example the first sample receiving portion, maybe connected to the driving system, while the other longitudinal end of the sample carrier, in a section of the sample carrier comprising for example the second sample receiving portion, may be connected to a tensioning element.

[0030] According to preferred embodiments, the driving system may comprise a motor configured for generating a rotational motion and a transmission element configured for transforming said rotational motion generated by the motor into said reciprocating movement of the first and second sample receiving portions. Apart from a rotational movement of a rotor of the motor, the motor may be substantially static with respect to the remaining components of the device, such that the motor does not increase a moving mass of the device, as opposed to systems known from the prior art that make use of a voice coil for generating a vibrating movement of the sample carrier. The motor may be configured for generating the reciprocating movement of the first and second sample receiving portions, for example as a sinus wave oscillation. The motor may be configured to operate with a rotational speed from l.ooo rpm to 100.000 rpm, preferably from 6.000 rpm to 60.000 rpm.

[0031] Preferably, the transmission element of the driving system may comprise an eccentric transmission element for transmitting a rotational motion generated by the motor to the sample carrier, in particular mechanically, preferably to one or both longitudinal ends thereof, as a reciprocating translational motion. In some embodiments, the transmission element may comprise a crankshaft comprising a first crank arm connected to one longitudinal end of the sample carrier and, optionally, a second crank arm connected to a second longitudinal end of the sample carrier, with the first sample receiving section arranged closer to the first longitudinal end than to the second longitudinal end and the second sample receiving section arranged closer to the second longitudinal end than to the first longitudinal end. The first crank arm and the second crank arm may be arranged on opposed sides of the rotation axis of the crankshaft, so as to generate the reciprocating movement of the first and second sample receiving portions with a phase difference of 180°. The use of such crankshaft allows generating the reciprocating movement of the sample carrier with minimal moving mass. In related embodiments, a transmission element other than a crankshaft, for example an eccentric transmission wheel, may be used. Preferably, the transmission element, for example the crankshaft, may comprise or be made of a metallic alloy, for example steel, in particular stainless steel, an aluminum-magnesium alloy, or of a polymer, for example carbon fiber enforced polymer,

[0032] In preferred embodiments, the first detection element comprises a first coil coiled around a first coil axis and the second detection element comprises a second coil coiled around a second coil axis parallel to the first coil axis. The first coil and the second coil are coiled or wound in opposite directions. This means that if the first coil is coiled clockwise, the second coil is coiled counterclockwise and vice versa. Other than that, the first and second coils may be identical, i.e., may have identical shape, geometry, number of windings, winding interspace and / or material composition. The first coil is coiled around a first coil axis and the second coil is coiled around a second coil axis that is parallel to the first coil axis. Possibly, the first coil axis and the second coil axis are aligned with each other and define the same axis, such that the first and second coils may be coaxial coils, and possibly but not necessarily overlapping coils. The first coil axis may be parallel to the second coil axis, be it in an aligned or coaxial configuration or in a non-aligned configuration.

[0033] According to preferred embodiments, the first sample receiving portion and the second sample receiving portion are movable with respect to each other, preferably in parallel and in front of each other, in particular in a direction parallel to the first and second coil axes. In preferred embodiments of the invention, each of the first and second sample receiving portions may comprise or be configured to receive an identical sample carrier element, possibly configured as a sample receiving substrate, arranged or arrangeable on the sample carrier, at a respective sample receiving portion. The sample carrier elements may be made of a polymer material, such as PEEK, Teflon, PE, PP, or PET, for example. A thin-layer sample may be arranged or arrangeable on the first or second sample carrier element. As previously explained, the configuration of a device according to the present invention is advantageous for all kinds of samples, but may be particularly advantageous for analysing properties of thin-layer samples, i.e., of samples having a thickness much smaller than a thickness of the underlying sample carrier element or sample receiving substrate on which the thin-layer sample may be arranged or deposited. For example, a thickness of the thin-layer sample may be from 1 nm to 1 pm, preferably from to nm to too nm, whereas a thickness of the first and second sample receiving substrates may be in a range of to pm to 5 mm, preferably from 0,5 mm to 2 mm. Since the first and second sample receiving substrates maybe identical, i.e., may have identical geometry and / or material composition, their contributions to the electrical currents and / or voltages induced upon the first and second coils can cancel off mutually, such that a measured net contribution may be provided by the thin-layer sample only, while substrate-caused distortions are eliminated.

[0034] In preferred embodiments, the first and second coils may have a circular, oval, quadrangular or polygonal cross-section. The geometry and size of a cross-section of the first and second coils may be adapted to the geometry of the sample, the properties of which are to be measured. Notably, increasing a ratio between a cross-section of the sample to be measured, in particular in a direction perpendicular to the first and second coil axes, and a cross-sectional surface of the first and second coils may increase the amplitude of the measurement signal measurable from the first and second coils, which further increases signal to noise ratio.

[0035] Thus, the device according to the present invention allows a mutual cancelation of the contributions to a measurement signal measured at the first and second coils not only of the sample carrier itself, i.e., of the first and second sample receiving portions, but also of the sample carrier element, like e.g. the sample receiving substrates that maybe arranged thereon, in particular when one of the sample receiving substrates carries a thin-layer sample arranged or deposited thereon.

[0036] According to preferred embodiments, the first and second sample receiving portions may be movable in parallel to the first and / or second coil axis and / or along the first and / or second coil axis. Thus, a direction in which the first and second sample receiving portions are movable may correspond to a direction defined by the first and second coil axes or at least parallel thereto. This may be the case, for example, when the sample carrier extends longitudinally through each of the first and second coils and coaxially with the first and second coils, with the first and second coils being arranged coaxially and aligned with each other, possibly around different sections of the sample carrier, with the first coil being for example arranged over the second coil or vice versa. This configuration may allow measuring directional properties of a sample being measured, for example a magnetization, in a direction corresponding to a direction defined by the first and second coil axes.

[0037] In further embodiments, the first and second sample receiving portions maybe movable partly perpendicularly to the first and / or second coil axis. Thus, a direction in which the first and second sample receiving portions are movable may have a component perpendicular to the directions defined by the axes of the first and second coils. This may be the case, for example when the sample carrier, in particular configured as a flexible continuous band, is guided such that sections thereof respectively containing the first and second sample receiving portions extend partly perpendicularly to the first and second coil axes, in particular between the first and second coil axes. This configuration may allow measuring directional properties of the sample being measured, for example a magnetization, in a direction perpendicular to a direction defined by the first and second coil axes.

[0038] A further aspect of the present invention refers to a magnetometer system comprising a device according to any of the previously described embodiments of the first aspect of the invention, and a measuring unit. The measuring unit maybe electrically connected to the first and second detection elements and may be configured for providing an output signal corresponding to a difference between a first measurement signal corresponding to a first current and / or voltage induced in the first detection element, in particular induced by a movement of sample carrier elements received on the sample carrier, and a second measurement signal corresponding to a second current and / or voltage induced in the second detection element, in particular induced by said movement of said sample carrier elements received on the sample carrier. One of the sample carrier elements or sample receiving substrates may have a thin-layer sample arranged or deposited thereon. The sample carrier is preferably configured such that the first and second detection elements are symmetrically configured and / or arranged with respect to the first and second sample receiving portions of the sample carrier.

[0039] The measuring unit may comprise hardware components for establishing such electrical connection to the first and second detection elements and may further comprise additional hardware and / or software components for providing the output signal as previously defined. In particular, the measuring unit may be partly implemented by a processing unit, such as a CPU or a general-purpose computer. The magnetometer system of the invention may further comprise a magnetic field generating device configured for generating an external magnetic field, in particular a constant magnetic field, in an environment of the device, and in particular of a sample to be measured, with predefined properties, in particular with predefined and controllable, preferably constant, magnetic field intensity.

[0040] In preferred embodiments, the magnetometer system may further comprise a cryostat, preferably a VTI cryostat. The sample carrier of the device, in particular the sample receiving portions thereof, may be at least partly or fully received within the cryostat. The cryostat may allow analysing properties of the sample to be measured using the device under controlled temperature conditions, in particular at controlled temperatures ranging for example from room temperature to about absolute zero temperature. The device may be adapted to a geometry of the cryostat, for example by correspondingly adapting a trajectory in space of the sample carrier, in particular when the sample carrier is configured as a flexible continuous band, such that the first and second sample receiving portions may be arranged in a section of the cryostat, in particular a middle section, at which the temperature and magnetic field external conditions may be most stable, homogeneous and / or optimally controllable. For example, in typical cryostats, such as in a typical VTI, which may have cylindrical geometry, for example having a diameter of 30 mm to 50 mm, the spatial region in which an external magnetic field may be most homogeneous may be at a depth of about 1.5 m half-way along the length of the cylinder.

[0041] In some embodiments, the magnetometer system may further comprise a rotation sensor configured for measuring a rotation speed corresponding to a reciprocating movement of the first and second sample receiving portions of the sample carrier of the device of the invention, for example a rotation speed of the previously mentioned transmission element of the device of the invention. The measuring unit may be connected to the rotation sensor and may further be configured for providing the output signal using the rotation speed measured by the rotation sensor as a reference signal or as a so-called “trigger signal”. The measuring unit may hence use the reference provided by the rotation sensor to provide the output signal corresponding to the difference between the first and second measurement signals. The rotation sensor may for example be implemented as an optical sensor, such as a light barrier sensor, which may for example be configured for detecting a rotational speed of the transmission element of the driving system of the device, for example of a crankshaft. Thanks to the reference provided by the rotation sensor, the output signal can be provided by the measuring unit with, increased accuracy. This is based on the principles of a so-called lock in amplifier (see e.g. https: / / en.wikipedia.org / wiki / Lock-in_amplifier) .Vention refers to a method for obtaining an output signal corresponding to a magnetization of a test sample, preferably using a device according to any of the previously described embodiments of the first aspect of the invention and / or a magnetometer system according to any of the previously described embodiments of the second aspect of the invention. The method may comprise: providing a first sample carrier element and a second sample carrier element in a magnetic field, wherein the first or second sample carrier element comprises the test sample arranged or deposited thereon, preferably deposited thereon as a thin layer, the first and second sample carrier elements preferably being identical; providing a first detection element and a second detection element in the magnetic field, wherein the first and second detection elements are configured and arranged with respect to the first and second sample carrier elements, such that, during a reciprocating movement of the first and second second sample carrier elements with respect to each other, variations in the magnetic field caused by the moving first and second sample carrier elements induce mutually cancelling electric currents and / or voltages upon the first and second detection elements; moving the first and second sample carrier elements with respect to each other reciprocatingly, such that variations in the magnetic field caused by the moving first and second sample carrier elements induce mutually cancelling electric currents and / or voltages upon the first and second detection elements, and obtaining the output signal corresponding to a difference between the first current or voltage and the second current or voltage.

[0042] Said magnetic field may in particular be a surrounding magnetic field, possibly a constant and / or homogeneous magnetic field, in which the first and second sample carrier elements and the test sample are arranged.

[0043] Preferably, the first and second sample carrier elements maybe respectively arranged in a first and second sample receiving portion of a sample carrier of a device according to the first aspect of the invention and the reciprocating movement of the first and second sample carrier elements may be driven by the driving system of a device according to the first aspect of the invention.

[0044] The method of the invention exploits symmetry to obtain an output signal that is free of contributions caused by the sample carrier elements themselves, which mutually cancel off, such that the output signal is related to the net contribution of the test sample to be measured. In other words, if the method were to be carried out in absence of the test sample, only with the sample carrier elements, the output signal corresponding to the difference between the first current or voltage and the second current or voltage would be zero or negligible due to the symmetry of the system, while, when the method is carried out with the test sample arranged on either one of the sample carrier elements, the output signal corresponds to the contribution of the test sample.

[0045] An additional aspect of the invention refers to a device for a magnetometer system, which may preferably be a gradiometer device, comprising a sample carrier, a driving system and a detection element. The sample carrier comprises a flexible continuous band, possibly a flexible continuous band as described above for the corresponding embodiments of the first aspect of the invention, wherein the flexible continuous band comprises a sample receiving portion for receiving thereon at least one sample. The driving system is configured for driving a reciprocating movement of the sample receiving portion of the sample carrier, possibly using any of the motion techniques described above for embodiments of the first aspect of the invention. The detection element is configured and arranged such that, when the sample receiving portion is exposed to a magnetic field and moved, a variation in said magnetic field caused by the moving sample receiving portion induces an electric current or voltage upon the detection element. The flexible continuous band comprises one or more turns, wherein the sample receiving portion preferably is arranged between two of the one or more turns, wherein the one or more turns more preferably comprise 90° turns.

[0046] BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Fig. 1 shows a scheme of a magnetometer system including a device according to an embodiment of the invention.

[0048] Fig. 2 shows a scheme of the magnetometer system of Fig. 1, wherein the device is received within a cryostat.

[0049] Fig. 3 shows a scheme of a magnetometer system including a device according to a further embodiment of the invention.

[0050] Fig. 4 shows a scheme of a magnetometer system including a device according to a further embodiment of the invention.

[0051] Fig. 5 shows a scheme of a magnetometer system including a device according to a further embodiment of the invention.

[0052] DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0053] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to specific preferred embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated apparatus and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur now or in the future to someone skilled in the art to which the invention relates within the scope defined by the claims.

[0054] Fig. 1 shows a schematic view of a magnetometer system 50 according to some embodiments of the invention comprising a device 10, configured as a gradiometer device, a measuring unit 52 and a rotation sensor 54. The device 10 comprises a first detection element and a second detection element, which are respectively configured in this embodiment as a first coil 12a and a second coil 12b. The first and second coils 12a and 12b are structurally and materially identical but for the fact that they are coiled in opposite directions around their respective coil axes Al and A2: the first coil 12a is coiled clockwise around the first coil axis Al and the second coil 12b is coiled counterclockwise around the second coil axis A2 or vice versa. The first and second coils 12a and 12b are coaxially arranged such that the first coil axis Al and the second coil axis A2 are parallel and aligned with each other.

[0055] The device 10 further comprises a continuous band-like sample carrier 14 made of a flexible material such as polyamide, Kapton, nylon, polyester or a combination thereof. Although the sample carrier 14 is substantially non-stretchable along its longitudinal direction, it is flexible such that it can be guided around first primary guiding elements 16a, 16b, such that a first portion 14a of the sample carrier 14 is arranged in Fig. 1 to the left of the first primary guiding elements 16a, 16b and a second portion 14b of the sample carrier 14 is arranged in Fig. 1 to the right of the first primary guiding elements 16a, 16b.

[0056] In the exemplary embodiment shown in Fig. 1, the primary guiding elements 16a, 16b are configured as rotating pulleys or rolling elements. The primary guiding elements 16a, 16b may rotate against the sample carrier 14 as the sample carrier 14 moves longitudinally. The primary guiding elements 16a, 16b guide a trajectory of the sample carrier 14 and allow the sample carrier 14 to form a U-turn that separates the first and second portions 14a, 14b of the sample carrier 14.

[0057] The opposed longitudinal ends of the sample carrier 14 are attached to opposed crank arms 24a, 24b of a driving system 20. The first crank arm 24a and the second crank arm 24b are arranged on opposed sides of the rotation axis R of the crankshaft. The driving system 20 comprises a motor 22 configured to generate a rotational motion and transmit it to a crankshaft 24. The crankshaft 24 is connected to respective longitudinal ends of the sample carrier 14, such that when driven by the motor 22, the crankshaft 24 transforms the rotational motion generated by the motor 22 into a reciprocating back-and-forth movement of the sample carrier Since the opposed longitudinal ends of the sample carrier are connected to opposed crank arms 24a, 24b of the crankshaft 24, the first and second portions of the sample carrier, the first portion 14a being arranged between the driving system 20 and the primary guiding elements 16a, 16b to the left as seen in in Fig. 1 and the second portion 14b being arranged between the driving system 20 and the primary guiding elements 16a, 16b to the right as seen in in Fig. 1, the first and second portions 14a, 14b of the sample carrier move antiphasically when driven by the driving system 20. This means that the first portion 14a moves forwards (downwards as seen in in Fig. 1) while the second portion 14b moves backwards (upwards as seen in Fig. 1) and vice versa. The reciprocating back-and-forth movement of the sample carrier is indicated in Fig. 1 by an arrow M.

[0058] The sample carrier 14 comprises a first sample receiving portion 13a comprised in the first portion 14a thereof arranged to the left between the primary guiding elements 16a, 16b and the driving system 20 and a second sample receiving portion 13b comprised in the second portion 14b thereof arranged to the right between the primary guiding elements 16a, 16b and the driving system 20. Each of the first and second sample receiving portions 14a, 14b is configured for receiving thereon a corresponding sample arrangement. The first sample arrangement, received on the first sample receiving portion 13 a, comprises a first sample carrier element, configured as a first sample receiving substrate 30a, and the second sample arrangement, received on the second sample receiving portion 13b, comprises a second sample carrier element, configured as a sample receiving substrate 30b and a thin-layer sample 32 arranged thereon, for example deposited thereon. The first and second sample receiving substrates 30a, 30b are identical substrates, in particular in terms of structure and material composition. According to an example, the substrates 30a, 30b have a thickness of 1 mm and the thin-layer sample 32 has a thickness of 50 nm. When the sample carrier 14 is driven by the driving system 20, the first and second sample receiving portions 14a, 14b, with the respective samples 30a, 30b, 32 received thereon, alternatingly move antiphasically back-and-forth. As a consequence, the first and second sample receiving substrates 30a, 30b, correspondingly move reciprocatingly. In the exemplary configuration shown in Fig. 1, the first and second sample receiving portions 14a, 14b of the sample carrier 14 move in parallel to the first and second coil axes Al, A2. The motion of the first sample receiving substrate 30a is within a first range of motion about a first zero -position and the motion of the second sample receiving substrate 30b, with the sample 32 thereon, is within a second range of motion about a second zero -position, wherein the first and second zero positions are arranged in front of each other, and wherein the first and second ranges of motion are also arranged in front of each other and fully overlapping with each other. In other configurations, the first and second sample receiving portions 14a, 14b of the sample carrier 14 can move partly perpendicularly to the first and second coil axes Al, A2, for example if the first and second coils 12a, 12b are arranged with a 450rotation as compared with the configuration illustrated in Fig. 1.

[0059] In the exemplary configuration of Fig. 1, the amplitude W of the crankshaft 24, i.e., a separation distance between the first and second crank arms 24a and 24b, corresponds to a maximal relative displacement of the first portion 14a of the sample carrier 14 with respect to the second portion 14b of the sample carrier 14. The amplitude W may be chosen such that the first and second sample receiving substrates 30a, 30b do not move past the first and second coils 12a, 12b. In such case, the first and second sample receiving portions 13a and 13b may correspond to a section of the sample carrier moving between the first and second coils 12a, 12b, respectively. Alternatively, the amplitude W may be chosen such that the first and second sample receiving substrates 30a, 30b move within a predefined length range, possibly across the first and second coils 12a, 12b. The first and second coils 12a, 12b may have a circular, oval, quadrangular or polygonal cross-section in a plane perpendicular to the respective coil axis Al, A2.

[0060] The magnetometer system 50 further comprises a measuring unit 52 that is electrically connected to each of the first and second coils 12a, 12b and configured for providing an output signal corresponding to a difference between a first measurement signal corresponding to a first current induced in the first coil 12a by the moving substrates 30a, 30b and the moving thin-layer sample 32 and a second measurement signal corresponding to a second current induced in the second coil 12b by the moving substrates 30a, 30b and the moving thin-layer sample 32.

[0061] For this purpose, the magnetometer system 50 is connected to a rotation sensor 54. The rotation sensor 54, which may be configured as a light barrier sensor, is configured for detecting a rotational speed of the crankshaft 24. The measuring unit 52 is configured for providing the output signal using the rotation speed measured by the rotation sensor 54 as a reference signal.

[0062] In the exemplary configuration of Fig. 1, the first and second coils 12a and 12b are connected in series to the measuring unit 52. However, in other related configurations, the first and second coils 12a and 12b can be connected in parallel to the measuring unit 52.

[0063] Advantageously, since the first and second sample receiving substrates 30a, 30b are identical and the first and second coils 12a, 12b only differ in their coiling direction, the contributions thereof as well as of the first and second portions of the sample carrier 14 itself to the output signal cancel off mutually, and the output signal better reflects properties of the sample 32 with improved signal-to-noise ratio and hence increased accuracy. Also indicated in Fig. 1 is an external magnetic field Bext, which maybe constant, that acts in an environment of the device 10, possibly having an influence on properties of the sample 32. The external magnetic field Bext may be generated by the magnetic field generating device. In the exemplary configuration shown in Fig. 1, the external magnetic field Bext is oriented vertically, i.e. parallel to the first and second coil axes Al and A2. However, in other related exemplary configurations, the external magnetic field can be oriented at least in part or totally horizontally, i.e. totally or partly perpendicular to the first and second coil axes Al and A2. This also applies to the configurations shown in each of Figs. 2-4.

[0064] Fig. 2 shows a further embodiment in which the magnetometer system 50 of Fig. 1 further comprises a cylindrical VTI cryostat 60, wherein the device 10, in particular the first and second sample receiving portions 14a and 14b with the substrates 30a, 30b and the sample 32 received thereon are received within the cryostat 60. The device 10 is arranged such that the first and second sample receiving portions 14a and 14b with the substrates 30a, 30b and the sample 32 received thereon are arranged in a middle longitudinal section of the cryostat 60. The cryostat 60 allows controlling a temperature of the sample 32, in particular within a temperature range from 40°C to approximately -271, 5°C.

[0065] Fig. 3 shows a further embodiment of a magnetometer system 50 according to the invention including a device 10. Elements corresponding to those previously described for the embodiments of Figs. 1 and 2 are indicated using the same reference numerals and are not explained in detail again for brevity.

[0066] As compared to the device 10 of Figs. 1 and 2, the device 10 of Fig. 3 differs by a slightly different path followed by the sample carrier 14. In the exemplary embodiment shown in Fig. 3, the first and second portions 14a, 14b of the sample carrier 14 are separated by a turn around section at which the sample carrier 14 is U-turned by three primary guiding elements 16a, 16b, 16c that are configured as rolling elements or pulleys. Further, each of the first and second portions 14a, 14b of the sample carrier 14 follows a non-straight path as guided by two respective secondary guiding elements isa-isd, 15a and 15b for the first portion 14a of the sample carrier 14 and 15c and 13d for the second portion 14b of the sample carrier 14, which create different portions of the sample carrier 14 that are mutually separated by one of the secondary guiding elements isa-isd and are angled with respect to each other.

[0067] A portion of the sample carrier arranged between the driving system 20 and the first secondary guiding element 15a is directed straight downwards but is angled with respect to a portion of the sample carrier arranged between the first and second secondary guiding elements 15a, 15b. A portion of the sample carrier arranged between the second secondary guiding element 15b and the primary guiding elements 16 is also directed straight downwards and angled with respect to the portion of the sample carrier arranged between the first and second secondary guiding elements 15a, 15b. The same applies to corresponding portions of the second portion 14b of the sample carrier with respect to the secondary guiding elements 15c and 13d.

[0068] A further difference of the device 10 of Fig. 3 as compared to the device 10 of Figs. 1 and 2 is the driving system 20, which in the embodiment of Fig. 3 is realized as a pair of coaxial eccentric wheels 26a, 26b rotatable around a rotation axis R by a driving wheel 23 connected to the motor 22. The eccentric wheels 26a and 26b rotate antiphasically, i.e., with a phase difference of 180°. An eccentric element 28a of the eccentric wheel 26a is attached to a longitudinal end of the first portion 14a of the sample carrier 14 and an eccentric element 28b of the eccentric wheel 26b is attached to a longitudinal end of the second portion 14b of the sample carrier 14. Thus, one of the eccentric wheels 26a drives a longitudinal end of the sample carrier 14 while the other eccentric wheels 26a drives a longitudinal end of the sample carrier 14, thereby generating the reciprocating movement of the sample carrier 14, and in particular of the sample receiving portions 13a, 13b thereof, which move in parallel and in front of each other. In this case, the rotation sensor 54 is configured for detecting a rotational speed of the eccentric wheel 26b.

[0069] Fig. 4 shows a further embodiment of a magnetometer system 50 according to the invention including a device 10. Elements corresponding to those previously described for the embodiments of Figs. 1 and 2 are indicated using the same reference numerals and are not explained in detail again for brevity.

[0070] As compared to the devices 10 of Figs. 1-3, the device 10 of Fig. 4 differs in that the first and second portions of the sample carrier 14 are materially disconnected instead of being different parts of a continuous band-like sample carrier. In this case, the sample carrier comprises a first sample carrier element 14-1 that comprises the first sample receiving portion 13a and is materially disconnected from a second sample carrier element 14-2 that comprises the second sample receiving portion 13b.

[0071] The first sample carrier element 14-1, in particular an upper longitudinal end thereof as seen in Fig. 4, is connected to the first crank arm 24a of the crankshaft 24, and a the second sample carrier element 14-2, in particular an upper longitudinal end thereof as seen in Fig. 4, is connected to the second crank arm 24b of the crankshaft 24. As a consequence, the rotational motion generated by the motor 22 is transformed by the crankshaft in an alternating reciprocating movement of the first and second sample carrier elements 14-1 and 14-2, which hence move antiphasically.

[0072] A bottom longitudinal end of each of the first and second sample carrier elements 14-1 and 14- 2 is attached to corresponding tensioning element 17a, 17b. Each of the tensioning elements 17a, 17b tensions a corresponding one of the first and second sample carrier elements 14-1 and 14-2. The tensioning elements 17a, 17b are connected between a respective one of the first and second sample carrier elements 14-1 and 14-2 and a stationary base 19. The stationary base 19 can for example be attached to a cryostat 60 in which the device 10 can be received (see Fig. 2) or correspond to an inner wall of the cryostat 60 itself.

[0073] In the exemplary configuration of Fig. 4, instead of being connected to a rotation sensor 54, the measuring unit 52 is connected to a control unit 25 of the motor 22 and is configured to obtained from the control unit 25 information about a rotational speed of the motor 22 and for using such information as a reference signal for obtaining the output signal. Fig. 4 shows a further embodiment of a magnetometer system 50 according to the invention including a device 10. Elements corresponding to those previously described for the embodiments of Figs. 1 to 4 are indicated using the same reference numerals and are not explained in detail again for brevity.

[0074] In the exemplary configuration shown in Fig. 5, the first and second sample receiving portions 13a, 13b are movable parallel to the first and second coil axes Al and A2, which are arranged perpendicular as compared to their arrangement in the previously described embodiments. This is achieved by correspondingly guiding the sample carrier 14 using secondary guiding elements isa-isd such that a portion of the sample carrier containing the samples 30a, 30b and 32 is correspondingly arranged parallel to the vertically arranged first and second coil axes Al and A2. This allows testing properties of the thin-layer sample 32 in a different arrangement as compared to the configurations shown in Figs. 1-4. In the exemplary configuration shown in Fig. 5, the first and second coils 12a and 12b are connected in parallel to the measuring unit 52. However, in other related configurations, the first and second coils 12a and 12b can be connected in series to the measuring unit 52. Notably, a section of the sample carrier 14 arranged horizontally between the secondary guiding elements 15a and 15c on one side and 15b and 13d on the other side can be small enough for the device 10 to fit into a cryostat, like the cryostat 60 shown in Fig. 2.

[0075] In the exemplary configuration shown in Fig. 5, the external magnetic field is oriented vertically, i.e. perpendicular to the first and second coil axes Al and A2. However, in other related exemplary configurations, the external magnetic field can be oriented at least in part or totally horizontally, i.e. totally or partly parallel to the first and second coil axes Al and A2.

[0076] Although preferred exemplary embodiments are shown and specified in detail in the drawings and the preceding specification, these should be viewed as purely exemplary and not as limiting the invention. It is noted in this regard that only the preferred exemplary embodiments are shown and specified, and all variations and modifications should be protected that presently or in the future lie within the scope of protection of the invention as defined in the claims.

Claims

CLAIMS1. A device (10) for a magnetometer system (50) comprising: a sample carrier (14) comprising a first sample receiving portion (13a) for receiving thereon a first sample carrier element and a second sample receiving portion (13b) for receiving thereon a second sample carrier element, wherein the first and second sample receiving portions (13a, 13b) are movable with respect to each other; a driving system (20) for driving a reciprocating movement of the first and second sample receiving portions (13a, 13b) such that the first and second sample receiving portions (13a, 13b) move antiphasically with respect to each other; and a first detection element (12a) and a second detection element (12b), wherein the first and second detection elements (12a, 12b) are configured and arranged with respect to the sample carrier (14), such that, during a reciprocating movement of the first and second sample receiving portions (13a, 13b) with respect to each other driven by the driving system (20), variations in a magnetic field caused by the moving first and second sample receiving portions (13a, 13b) induce mutually cancelling electric currents and / or voltages upon the first and second detection elements (12a, 12b).

2. The device (10) of claim 1, wherein each of the first and second sample receiving portions (13a, 13b) comprises an identical sample carrier element, possibly configured as a sample receiving substrate (30a, 30b), arranged or arrangeable on the sample carrier (14), wherein one of the first and second sample carrier elements preferably comprises a thin-layer sample (32) arranged or arrangeable thereon.

3. The device (10) of claim 1 or 2, wherein the sample carrier (14) comprises a flexible continuous band, wherein the first and second sample receiving portions (13a, 13b) are different portions of the band.

4. The device (10) of any of the preceding claims, wherein the band is made of a material being or comprising polyamide, Kapton, nylon, polyester or a combination thereof.

5. The device (10) of claim 3 or 4, further comprising a one or more primary guiding elements (16; 16a, 16b, 16c), preferably one or more rolling elements or pulleys, for guiding a trajectory in space of the sample carrier (14), wherein the first sample receiving portion (13a) and the second sample receiving portion (13b) are separated by the one or more primary guiding elements (16; 16a, 16b, 16c), such that the first sample receiving portion (13a) and the second sample receiving portion (13b) preferably extendin parallel and in front of each other on different sides of the one or more primary guiding elements (16; 16a, 16b, 16c).

6. The device (10) of any of claims 3 to 5, further comprising one or more secondary guiding elements (15a, 15b, 15c, 13d), preferably one or more pulleys, for guiding a trajectory in space of the sample carrier (14), wherein different portions of the sample carrier (14) are separated by one of the one or more secondary guiding elements (15a, 15b, 15c, 13d) and are preferably angled with respect to each other.

7. The device (10) of claim 1 or 2, wherein the first sample receiving portion (13a) and the second sample receiving portion (13b) are materially disconnected from each other.

8. The device (10) of any of the preceding claims, further comprising at least a tensioning element (17a, 17b) configured for tensioning the sample carrier (14), wherein the at least one tensioning element (17a, 17b) is preferably connected to a respective longitudinal end of the sample carrier (14) and / or of a respective one of the first or second sample receiving portion (13a, 13b).

9. The device (10) of any of the preceding claims, wherein the driving system (20) comprises a motor (22) for generating a rotational motion and a transmission element (24) configured for transforming said rotational motion generated by the motor (22) into said reciprocating movement of the first and second sample receiving portions (13a, 13b).

10. The device (10) of claim 9, wherein the transmission element (24) comprises a crankshaft comprising a first crank arm (24a) connected to a first longitudinal end of the sample carrier (14) and optionally a second crank arm (24b) connected to a second longitudinal end of the sample carrier (14), wherein the first crank arm (24a) and the second crank arm (24b) are preferably arranged on opposed sides of a rotation axis (R) of the crankshaft.

11. The device (10) of any of the preceding claims, wherein the first detection element comprises a first coil (12a) coiled around a first coil axis (Al) and the second detection element comprises a second coil (12b) coiled around a second coil axis (A2) parallel to the first coil axis (Al), wherein the first and second coils (12a, 12b) are coiled in opposed directions;wherein the first and second sample receiving portions (13a, 13b) are preferably movable with respect to the first and second coil axes (Al, A2) in parallel and in front of each other; and / or wherein the driving system (20) is preferably configured for driving said reciprocating movement of the first and second sample receiving portions (13a, 13b) with respect to the first and second coil axes (Al, A2).

12. The device (10) of claim 11, wherein the first and second coils (12a, 12b) have a circular, oval, quadrangular or polygonal cross-section.

13. The device (10) of claim 11 or 12, wherein the first and second sample receiving portions (13a, 13b) are movable along the first and / or second coil axis (Al, A2) and / or parallel to the first and / or second coil axis (Al, A2).

14. The device (10) of claim 11 or 12, wherein the first and second sample receiving portions (13a, 13b) are movable perpendicularly to the first and / or second coil axis (Al, A2).

15. A magnetometer system (50) comprising: a device (10) according to any of the preceding claims; and a measuring unit (52) electrically connected to the first and second detection elements (12a, 12b) and configured for providing an output signal corresponding to a difference between a first current and / or voltage induced in the first detection element (12a) and a second current and / or voltage induced in the second detection element (12b).

16. The magnetometer system (50) of claim 15, further comprising a cryostat (60), preferably a VTI cryostat, wherein the sample carrier (14) of the device (10), in particular the first and second sample receiving portions (13a, 13b) thereof, is at least partly received within the cryostat (60).

17. The magnetometer system (50) of claim 15 or 16, further comprising a rotation sensor (54) configured for measuring a rotation speed corresponding to a reciprocating movement of the first and second sample receiving portions (13a, 13b) of the sample carrier (14) of the device (10), wherein the measuring unit (52) is connected to the rotation sensor and is further configured for providing the output signal using the rotation speed measured by the rotation sensor as a reference signal.

18. A method of obtaining an output signal corresponding to a magnetization of a test sample (32), preferably using a device (10) according to any of claims 1 to 15 and / or a magnetometer system (50) according to any of claims 15 to 17, the method comprising: providing a first sample carrier element (30a) and a second sample carrier element (30b) in a magnetic field, wherein the first sample carrier element (30a) or the second sample carrier element (30b) comprises the test sample (32) arranged thereon, preferably deposited thereon as a thin layer, the first and second sample carrier elements (30a, 30b) preferably being identical; providing a first detection element (12a) and a second detection element (12b) in the magnetic field, wherein the first and second detection elements (12a, 12b) are configured for supporting a respective induced electric current or voltage and are configured and arranged with respect to the first and second sample carrier elements (30a, 30b), such that, during a reciprocating movement of the first and second sample carrier elements (30a, 30b) with respect to each other, variations in the magnetic field caused by the moving first and second sample carrier elements (30a, 30b) induce mutually cancelling electric currents and / or voltages upon the first and second detection elements (12a, 12b); moving the first and second sample carrier elements with respect to each other reciprocatingly, such that variations in the magnetic field caused by the moving first and second sample carrier elements induce mutually cancelling electric currents and / or voltages upon the first and second detection elements, and obtaining the output signal corresponding to a difference between the first current or voltage and the second current or voltage.

19. A device (10) for a magnetometer system (50) comprising: a sample carrier (14) comprising a flexible continuous band with a sample receiving portion (13a; 13b) for receiving thereon at least one sample; a driving system (20) for driving a reciprocating movement of the sample receiving portion; and a detection element (12a; 12b), configured and arranged such that, when the sample receiving portion (12a; 12b) is exposed to a magnetic field and moved, a variation in said magnetic field caused by the moving sample receiving portion (13a; 13b) induces an electric current or voltage upon the detection element (12a; 12b); wherein the flexible continuous band comprises one or more turns, wherein the sample receiving portion preferably is arranged between two of the one or more turns, wherein the one or more turns more preferably comprise 90° turns.

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