Excitation and detection element for in-situ nuclear and / or electron spin resonance spectroscopy in a transmission electron microscope

Abstract

A nuclear spin and / or electron spin resonance excitation and detection element (1) for in-situ nuclear and / or electron spin resonance spectroscopy in a Transmission Electron Microscope (TEM) comprising: - a body part (3), wherein the body part (3) is configured for receiving a sample (23) on or within the body part (3); and - an electrical circuit (5), preferably a resonator circuit, configured for emitting an electromagnetic excitation signal and for receiving an electromagnetic response signal from a sample (23) on or within the body part (3), wherein the electrical circuit (5) is arranged on or within the body part (3).

Description

[0001] Excitation and detection element for in-situ nuclear and / or electron spin resonance spectroscopy in a Transmission Electron Microscope

[0002] The present invention relates to microwave spectroscopy, in particular spin resonance spectroscopy or magnetic resonance spectroscopy, in combination with transmission electron microscopy . In particular the present invention relates to a nuclear spin and / or electron spin resonance excitation and detection element for in-situ nuclear and / or electron spin resonance spectroscopy in a Transmission Electron Microscope ( TEM) with a body part , wherein the body part is configured for receiving a sample on or within the body part , as well as a method for in-situ spin resonance spectroscopy within a Transmission Electron Microscope ( TEM) .

[0003] Coherent spin resonance methods such as nuclear magnetic resonance (NMR) and electron spin resonance (ESR) spectroscopy have led to spectrally highly sensitive , non-invasive quantum imaging techniques with groundbreaking applications in medicine , biology, and physics . Similarly, but with different capabilities , transmission electron microscopy offers detailed investigations at even subatomic resolution, however, often accompanied by severe radiation damage .

[0004] Transmission electron microscopy with its various recent innovations like aberration correction or cryo sample preparation, is a highly developed technology that employs wave properties of electrons to resolve structures at an atomic level . The development of fast direct electron detectors ( see for example X . Llopart , J . Alozy, R . Ballabriga, et al . , Timepix4 , a large area pixel detector readout chip providing sub-200 ps timestamp binning, Journal of Instrumentation 17 ( 01 ) , C01044 , ( 2022 ) ) and ultra- fast transmission electron microscopic techniques enabled the investigation of processes with both atomic scale spatial resolution and sub-picosecond temporal resolution ( see for example V . A. Lobastov, R . Srinivasan, and A. H . Zewail , Fourdimensional ultrafast electron microscopy, Proceedings of the National Academy of Sciences 102 , 7069 ( 2005 ) ; and A. H .

[0005] Zewail , 4D ultrafast electron diffraction, crystallography, and microscopy, Annual Review of Physical Chemistry 57, 65 (2006) ) , with even specially optimized interferometric setups (see for example F. Houdellier, G. M. Caruso, S. Weber, et al., Optimization of off-axis electron holography performed with femtosecond electron pulses, Ultramicroscopy 202, 26 (2019) ; and A. Arbouet, G. M. Caruso, and F. Houdellier, Ultrafast transmission electron microscopy: historical development, instrumentation, and applications, Advances in imaging and electron physics 207, 1 (2018) ; as well as A. Feist, N. Bach, N. Rubiano da Silva, et al., Ultrafast transmission electron microscopy using a laser-driven field emitter: Femtosecond resolution with a high coherence electron beam, Ultramicroscopy 176, 63 (2017) ) .

[0006] Mainly in transmission electron microscopy, the sample is arranged in the TEM by means of a sample holder. Such sample holders typically comprise an elongated part, which comprises an element for holding the sample in place, such that an electron beam of the TEM can interact with the sample. Sample holders are well known in the art and are commercially available in various configurations. In addition to a mechanical fixation of the sample, holders can be configured to provide additional functions. For example, holders can be configured to cool or heat the sample, or, for example, to irradiate the sample with an electromagnetic signal in order to manipulate properties of the sample before, during or after a TEM experiment or investigation.

[0007] For example, US 11 410 829 Bl shows a TEM sample holder with a cryogenic cooling and broadband radio frequency (RE) irradiation. The sample holder comprises a coaxial conductor, which is configured to provide simultaneous cooling and RE irradiation to a sample while the sample is being exposed to electrons applied thereto. The holder may be used to implement pump and probe experiments, wherein the sample is imaged synchronously with the delivery of pulsed or continuous electrons to the sample in order to investigate electrical stimuli in the radio and microwave frequency regime. In addition to a holder, further add-ons , which provide additional functionalities may be inserted into the TEM ( i . e . , into a vacuum column or vacuum chamber of the TEM) and placed adj acent to the sample , which is arranged on a separate sample holder . Structurally, such an add-on is typically similar to a holder - except that the add-on typically does not provide tailored means for holding the sample and can be therefore utili zed independently of the sample . These add-ons can be used in combination with a sample holder, which provides other or complementary ( speciali zed) functionalities .

[0008] Resonance spectroscopy, in particular spin resonance spectroscopy or magnetic resonance spectroscopy techniques such as , for example , nuclear magnetic resonance (NMR) and electron spin resonance (ESR) , is a non-invasive spectroscopic ( imaging) technology that has revolutioni zed not only medical diagnostics , biology, and chemistry but also high-precision measurements for fundamental physics . Additionally, it is also used for characteri zing electrode materials for electrochemical energy storage . ESR, for example , plays a pivotal role in investigating chemical reactions during electrolytic processes critical for battery research, polymer characteri zation and dosimetry for the evaluation of radiation caused damage .

[0009] Spin or magnetic resonance spectroscopy and transmission electron microscopy are complementary to each other and provide di f ferent insights into structures , materials , and ( chemical ) processes . While magnetic resonance spectroscopy techniques are typically non-invasive and have an excellent spectral resolution, electron microscopy has a superior spatial resolution . However, in order to investigate a sample with these complementary methods , the sample needs to be trans ferred between a TEM and an ESR spectrometer and / or an NMR spectrometer . Since especially the trans fer into and out of a TEM is complex due to the vacuum within the TEM and the tedious sample preparation for TEM investigations , such a trans fer is time consuming and prone to errors such as a contamination of the sample . In addition, properties of the sample can change within the time that is necessary for trans ferring the sample . In particular, biological or chemical reactive samples may degrade or at least change over time . It is therefore not always possible to combine results from a TEM investigation and an earlier or subsequent ESR / NMR investigation .

[0010] Due to the complex and carefully aligned magnetic field ( s ) within a TEM, which are crucial for shaping and guiding the electron beam, it is hardly possible to include an ESR or NMR spectrometer into a TEM, since the former also generate strong magnetic fields , which would disturb the magnetic field of the TEM and vice versa .

[0011] It is therefore an obj ect of the invention to alleviate or eliminate at least some of the drawbacks of the prior art . Preferably, it is an obj ect of the invention to provide a nuclear spin and / or electron spin resonance excitation and detection element for in-situ nuclear and / or electron spin resonance spectroscopy in a Transmission Electron Microscope ( TEM) as well as a method for in-situ spin resonance spectroscopy within a Transmission Electron Microscope ( TEM) , which allows the parallel and / or subsequent investigation of a sample with the electron beam of the TEM as well as nuclear and / or electron spin resonance spectroscopy .

[0012] This obj ect is solved by a nuclear spin and / or electron spin resonance excitation and detection element for in-situ nuclear and / or electron spin resonance spectroscopy in a Transmission Electron Microscope ( TEM) comprising :

[0013] - a body part , wherein the body part is configured for receiving a sample on or within the body part ; and

[0014] - an electrical circuit , preferably a resonator circuit , configured for emitting an electromagnetic excitation signal and for receiving an electromagnetic response signal from a sample on or within the body part , wherein the electrical circuit is arranged on or within the body part .

[0015] The obj ect is also solved by a transmission electron microscope for in-situ nuclear and / or electron spin resonance spectroscopy comprising :

[0016] - a sample holder configured to hold a sample ;

[0017] - an electron source for irradiating the sample with an electron beam; -an electron detector unit for detecting the electron beam;

[0018] - a magnetic field generator for generating a magnetic bias field, wherein the magnetic bias field at the sample is essentially parallel to a main axis of the electron beam; and a nuclear spin and / or electron spin resonance excitation and detection element according to the invention, wherein the sample holder is configured to hold the sample on or within the body part of the nuclear spin and / or electron spin resonance excitation and detection element .

[0019] Furthermore , this obj ect is solved by a method for in-situ spin resonance spectroscopy within a Transmission Electron Microscope ( TEM) according to the invention with the steps :

[0020] - providing a sample , wherein the sample holder holds the sample within the TEM;

[0021] - generating a magnetic bias field by the magnetic field generator, wherein the sample is within the magnetic bias field;

[0022] - irradiating the sample with an electromagnetic excitation signal generated by the electrical circuit ;

[0023] - receiving an electromagnetic response signal from the sample by the electrical circuit ; and

[0024] - detecting a spin resonance of the sample based on the electromagnetic response signal .

[0025] Transmission electron microscopes ( TEM) are well known in the art . The TEM preferably comprises a column for an electron beam, which is used to investigate a sample . The column is preferably configured as a vacuum chamber . The TEM comprises an electron source for generating the electron beam . The electron source may be referred to as an electron gun . Preferably, the column is arranged vertically, whereas the electron source may be arranged at a top end of the column . In order to shape and guide the beam, a TEM may comprise multiple magnetic field units , which may be arranged in the column . The TEM furthermore comprises a sample holder configured to hold the sample . The sample holder may be arranged within the column, such that the electron beam can interact with the sample . In addition, the TEM comprises an electron detector for detecting the electron beam . The electron detector may be arranged to detect electrons, which are transmitted through the sample. The sample may be arranged downstream (with respect to the electron beam) of the electron source. The electron detector may be arranged downstream of the sample. The electron detector may be configured as a bright field or a dark field detector. The TEM may comprise further electron detectors, for example to detect electrons, which are scattered and / or reflected by the sample. The detector may comprise a charge-coupled device or a CMOS detector element, for example. The detector unit may comprise a CCD camera, a CMOS camera, a pixel array detector or an active pixel sensor, for example. The column may comprise at least one port, through which, for example, the sample holder may be inserted.

[0026] The sample may comprise any material, such as any inorganic or organic material. The sample may comprise a gas, and / or a liquid and / or a solid. For example, the sample may comprise a biological probe material, such as a biological tissue or a biological substance. The sample may comprise a nuclear and / or an electron spin resonance with an energy gap matching a radio-frequency of an electromagnetic radiation and / or electromagnetic evanescent field (or near field) , such that the spin resonance is driven (e.g., excited) when the sample is exposed to electromagnetic radiation comprising a corresponding radio-frequency, as is well known in the field of spin resonance spectroscopy, such as in nuclear magnetic resonance spectroscopy (NMR) , nuclear quadrupole resonance spectroscopy (NQR) and electron spin resonance spectroscopy (ESR) . The energy gap of the two spin states for ESR / NMR can be changed (i.e., manipulated) by means of a magnetic field. This is known as Zeeman splitting or Zeeman effect. Fundamentals of nuclear magnetic resonance are for example known from Gutowsky, H. S. "Nuclear magnetic resonance." Annual Review of Physical Chemistry 5, 1 (1954) : 333-356. Fundamentals of electron spin resonance (ESR) are for example known from Freed, Jack H. "New technologies in electron spin resonance." Annual review of physical chemistry 51, 1 (2000) : 655-689.

[0027] The nuclear spin and / or electron spin resonance excitation and detection element for in-situ nuclear and / or electron spin resonance spectroscopy in the Transmission Electron Microscope ( TEM) comprises a body part , wherein the body part is configured for receiving a sample on or within the body part . The body part may be configured for holding the sample , e . g . , the body part may comprise means for holding the sample at a predefined location . The body part may be configured to receive the sample without holding the sample . For example , a ( standard) TEM sample holder may be used to hold the sample , for example , within the body part . The body part may or may not be in physical contact with the sample . The body part may be or may comprise an elongated member . The body part may comprise a length of 10 to 50 cm . The body part may comprise an essentially circular cross section ( orthogonal to the length) . The body part may comprise an essentially rectangular cross section . The cross section may comprise a diameter between 1 and 40 mm .

[0028] The body part may be configured to receive the sample , in intended use to receive the sample within the TEM . The body part may comprise an opening through which an end portion or a tip of the sample holder may be inserted into the body part . A sample on the sample holder may be enclosed by the body part , for example .

[0029] The body part may comprise a metal and / or a polymer . In particular, the body part may comprise steel , copper, aluminum and / or brass . The body part is configured for insertion into the TEM, in particular into the column of the TEM through a port or vacuum feedthrough . The nuclear spin and / or electron spin resonance excitation and detection element may comprise further members connected to the body part . The nuclear spin and / or electron spin resonance excitation and detection element may comprise a member configured for connection to a flange of a vacuum chamber ( e . g . , a column) of the TEM .

[0030] The nuclear spin and / or electron spin resonance excitation and detection element furthermore comprises an electrical circuit , preferably a resonator circuit , configured for emitting an electromagnetic excitation signal and for receiving an electromagnetic response signal from a sample on or within the body part , wherein the electrical circuit is arranged on or within the body part . The electrical circuit may comprise an electrical line and at least one circuit element , such as a capacitor, a resistor, and / or an inductance . The electrical circuit may comprise discrete components . The circuit may be a distributed-element circuit comprising lengths of transmission lines or other distributed components . Distributed element circuits may perform the same functions as conventional electrical circuits composed of passive components , such as capacitors , inductors , and trans formers . The electrical circuit may be arranged on a surface of the body part . The electrical circuit may be arranged at least partially within the body part . The body part may at least partially surround the electrical circuit .

[0031] The body part may comprise at least one feedthrough in order to establish an electrical connection, for example , by means of a cable , in particular a coaxial cable . The electrical circuit may be connected to an external device through the at least one feedthrough . The external device may be outside the column of the TEM, i . e . outside vacuum during intended use of the TEM .

[0032] The electrical circuit is configured for emitting an electromagnetic excitation signal and for receiving an electromagnetic response signal from a sample on or within the body part . The electrical circuit may be a resonator circuit and may comprise a resonance frequency . The electrical circuit may be connected to an external device , such as a function generator, and may receive an electrical signal comprising the resonance frequency from the external device . The electrical circuit may comprise , for example , an antenna for emitting the electromagnetic excitation signal . The electromagnetic excitation signal comprises a frequency, for example the resonance frequency . The sample may be excited by the electromagnetic excitation signal , i . e . , an electron spin resonance and / or a magnetic resonance of the sample may be excited . The frequency of the electromagnetic excitation signal may correspond to a resonance frequency of the sample . The frequency of the electromagnetic excitation signal may be in the range of a few mHz ( for example , 100 mHz ) to 300 GHz , for example . The electromagnetic excitation signal may be a continuous signal ( e . g . , for continuous wave ( CW) ESR) . Alternatively, the electromagnetic excitation signal may comprise at least one pulse or a pulse train, for example with a pulse length in between 1 ps and a few tens of seconds , for example 60 s ( e . g . , for pulsed ESR / NMR) .

[0033] For example , for electron spin resonance spectroscopy, an external magnetic field is used to separate an energy level of a spin up electron from the energy level of a spin down electron . According to the invention, the magnetic field of the TEM, which is used in order to shape and / or guide the electron beam, is ( also ) used to split the energy levels of the sample accordingly . In other words , the same magnetic field that guides the electrons of the electron beam of the TEM is used to bias the sample accordingly, such that , for example , an electron spin resonance spectroscopy may be performed within ( and with) the TEM .

[0034] The electrical circuit is not only configured for emitting the electromagnetic excitation signal , but for receiving an electromagnetic response signal from the sample . The excited sample may emit an electromagnetic response signal due to a relaxation process or may ref lect / manipulate a portion of the electromagnetic excitation signal , wherein the ref lected / manipulated portion contributes to the electromagnetic response signal . A resonance frequency of the electromagnetic response signal may be essentially equal to the resonance frequency of the electromagnetic excitation signal . For example , the electrical circuit may be configured for receiving the electromagnetic response signal from the sample by means of the antenna . The electromagnetic response signal may be transmitted through the feedthrough of the body part and may be received by a detection unit . Based on the electromagnetic response signal , a resonance of the sample may be detected .

[0035] By means of the nuclear spin and / or electron spin resonance excitation and detection element , in-situ nuclear and / or electron spin resonance spectroscopy can be performed in ( i . e . within) a Transmission Electron Microscope ( TEM) , i . e . in- situ . The sample may remain inside the vacuum of the TEM and does not need to be removed from the TEM . Therefore , the sample can be investigated by means of transmission electron microscopy and by means of nuclear and / or electron spin resonance spectroscopy utili zing only one instrument : a TEM with the nuclear spin and / or electron spin resonance excitation and detection element according to the invention . This allows the parallel and / or subsequent investigation of the sample with the electron beam of the TEM as well as nuclear and / or electron spin resonance spectroscopy . In addition, the electron beam may be used to probe properties of the sample before and after electromagnetic excitation .

[0036] The transmission electron microscope ( TEM) for in-situ nuclear and / or electron spin resonance spectroscopy comprises :

[0037] - a sample holder configured to hold a sample ;

[0038] - an electron source for irradiating the sample with an electron beam;

[0039] -an electron detector unit for detecting the electron beam;

[0040] - a magnetic field generator for generating a magnetic bias field, wherein the magnetic bias field at the sample is essentially parallel to a main axis of the electron beam . The magnetic field generator may comprise one or more magnets . In particular, the magnetic field generator may be configured to generate one or more magnetic lenses . For example , a condenser lens may be formed to control the convergence of electron emitted by the electron source . Furthermore , an obj ective lens may be generated . The obj ective lens may be arranged adj acent to the sample holder . A proj ector lens may be generated, which is configured for proj ecting an image of the sample onto the detector . Additionally, further intermediate lenses may be generated . The magnetic field generator may comprise one or more pole shoes to concentrate the magnetic field . In the context of the invention and with respect to in-situ nuclear and / or electron spin resonance spectroscopy, the magnetic field within the TEM and in particular in the vicinity of the sample holder and the sample is referred to as bias field . In particular, the part of the magnetic field that generates the obj ective lens may be in the vicinity of the sample . At the location of the sample , for example , within the sample , the magnetic bias field is essentially parallel to a main axis of the electron beam . The magnetic bias field may comprise transverse magnetic field ( i . e . , B- field) components and may comprise a gradient for focusing / manipulating the electron beam . A si ze of the sample may be small compared to the gradient of the magnetic bias field . Therefore , the magnetic bias field may be considered homogeneous at and / or within the sample . For example , the sample holder ( and therefore the sample ) may be arranged in between two pole shoes , such that the magnetic bias field is essentially parallel to the electron beam ( at least at the location of the sample ) . The magnetic bias field may be the magnetic field within the TEM generated by the magnetic field generator, which ef fectively interacts with the sample .

[0041] Furthermore , the TEM according to the invention comprises the nuclear spin and / or electron spin resonance excitation and detection element . The sample holder is configured to hold the sample on or within the body part of the nuclear spin and / or electron spin resonance excitation and detection element . The nuclear spin and / or electron spin resonance excitation and detection element may be an add-on, which may be manipulated independently of the sample holder . For example , the add-on may be mounted such that it can easily be removed from the sample holder and added to the sample holder . For example , the add-on may comprise an opening for receiving the sample holder . The add-on may, for example , be removed in order to perform standard transmission electron microscopy . The add-on may be used to perform in-situ nuclear and / or electron spin resonance spectroscopy within and with the TEM .

[0042] Optionally, the body part may comprise an electron passage , wherein the electron passage is configured as a passage for an electron beam of a TEM, wherein the body part is configured for receiving a sample within the electron passage . The electron passage may be formed by, for example , a hole or a feedthrough in the body part . The electron passage may have a main axis . The main axis of the body part may be transverse , in particular orthogonal to a main axis of extension of the body part . The electron passage may extend from a top surface of the body part to a bottom surface of the body part . The nuclear spin and or electron spin resonance excitation and detection element may be arranged in the TEM (i.e., in a vacuum chamber of the TEM) , such that the main axis of the electron beam is essentially parallel to the main axis of the electron passage. The electron passage may comprise a diameter of 1 pm to 3 cm, for example.

[0043] The electromagnetic excitation signal is preferably transverse, in particular orthogonal to the magnetic bias field to enhance the excitation efficiency. Therefore, the electromagnetic excitation signal is preferably transverse, in particular orthogonal to main axis of the electron passage.

[0044] The electrical circuit may optionally be impedance matched to a frequency of the electromagnetic excitation signal and / or the electromagnetic response signal. This leads to a particular efficient emission of the electromagnetic excitation signal and / or detection of the electromagnetic response signal.

[0045] Optionally, the electrical circuit may comprise an antenna, in particular a micro-strip resonator (which is an embodiment of an antenna) , wherein the antenna is preferably arranged adjacent to the electron passage or within the electron passage. By means of an antenna, the electromagnetic excitation signal can be emitted efficiently. In addition, the electromagnetic response signal can be received efficiently. The antenna may have a directionality and may be arranged such that the electromagnetic excitation signal is emitted in direction of the sample or an intended location of the sample on the sample holder. A planar micro-strip resonator is, for example, known from Narkowicz, R., Suter, D., & Stonies, R. (2005) . Planar microresonators for EPR experiments. Journal of

[0046] Magnetic Resonance, 175(2) , 275-284. Another planar microstrip microresonator is known from Narkowicz, R., Suter, D., & Niemeyer, I. (2008) . Scaling of sensitivity and efficiency in planar microresonators for electron spin resonance. Review of Scientific Instruments, 79(8) . The nuclear spin and / or electron spin resonance excitation and detection element may comprise a printed circuit board ( PCB ) , wherein the PCB comprises the antenna . For example , the PCB may comprise a metallic layer . The metallic layer may form the antenna, in particular the micro-strip resonator . Alternatively or additionally to the PCB, the nuclear spin and / or electron spin resonance excitation and detection element may comprise a breadboard, a perfboard, and / or a stripboard, for example .

[0047] The nuclear spin and / or electron spin resonance excitation and detection element may comprise a modulation coil configured for generating a magnetic modulation field, wherein the magnetic modulation field is preferably essentially parallel to a main axis of the electron passage in at least a section of the electron passage . The modulation coil may be an air coil , for example . The modulation coil may comprise a main coil axis . A center of the modulation coil may lie on the main coil axis . The modulation coil may comprise at least one winding ( i . e . , turn) of a wire , preferably at least two windings , in particular at least three windings of a wire . The wire may be turned around the main coil axis . The main coil axis may coincide with the main axis of the electron passage , such that the magnetic modulation field is parallel to the main axis of the electron passage in at least a section of the electron passage .

[0048] The nuclear spin and / or electron spin resonance excitation and detection element may comprise a sample arranged within the electron passage , wherein the magnetic modulation field is essentially parallel , to the main axis of the electron passage at least at a location of the sample . In order to enhance the sensitivity and / or reduce noise sources of an ESR and / or NMR measurement , a magnetic modulation field may be used . The modulation field may comprise a modulation frequency . The modulation field allows , for example , the use of lock-in ampli fiers to detect the electromagnetic response signal with enhanced sensitivity signi ficantly improves the signal-to- noise ratio ( SNR) . The magnetic modulation field is an electromagnetic field . An overall magnetic field at the location of the sample comprises the magnetic bias field and, in addition, the modulation field . The magnetic bias field may be a static field . The modulation field is a time-dependent ( i . e . , oscillating) field . The magnetic bias field may comprise a magnetic field strength of 0 to 4 T ( Tesla ) . The magnetic modulation field may comprise an amplitude of 10 mT , for example . The magnetic modulation field may be essentially parallel to the magnetic bias field at the location of the sample . The magnetic modulation field may be essentially parallel to the magnetic bias field at the location of the sample . Since the magnetic bias field is essentially parallel to the main axis of the electron passage , the magnetic modulation field may be essentially parallel to the main axis of the electron passage .

[0049] Optionally, the sample holder may be the nuclear spin and / or electron spin resonance excitation and detection element or may comprise the nuclear spin and / or electron spin resonance excitation and detection element . The sample holder for a Transmission Electron Microscope ( TEM) for in-situ nuclear and / or electron spin resonance spectroscopy in a TEM, may comprise the nuclear spin and or electron spin resonance excitation and detection element , wherein the body part is configured to hold a sample , preferably within the electron passage . For example , the body part may comprise a plate for receiving and holding the sample within the electron passage . The sample holder, in particular the body part , may comprise a clamping mechanism for securing ( i . e . , holding) a sample . The clamping mechanism may comprise a fastening system, for example , a spring-loaded clip .

[0050] Optionally, a main axis of the electron passage is essentially parallel to the main axis of the electron beam, wherein the electron beam is configured to pass through the electron passage , wherein the sample holder is configured to hold the sample within the electron passage .

[0051] Optionally, the TEM may comprise a radio- frequency signal generator for generating a radio frequency signal , wherein the radio- frequency signal generator is connected to the electrical circuit , such that the electrical circuit receives the radio frequency signal . The radio- frequency signal generator may be a function generator . The radio- frequency signal generator may be configured for generating a microwave signal , for example , comprising a frequency in between 300 Hz and 300 GHz . The radio- frequency signal generator may be arranged outside the column . The radio- frequency signal generator may be an external device .

[0052] Optionally, the TEM may comprise a modulation signal generator for generating a modulation signal , wherein the modulation signal generator is connected to the modulation coil , such that the modulation coil receives the modulation signal . The modulation signal generator may be a function generator . The modulation signal generator may be connected to the modulation coil by mean of a cable , in particular a coaxial cable . The modulation signal generator may be connected to the modulation coil through a feed-through of the body part . The column of the TEM may also comprise a f eed-through, such that the modulation coil is connected to the modulation signal generator through the feed-through of the body part and the feed-through of the column of the TEM .

[0053] The sample holder of the TEM may comprise the spin resonance excitation and detection element .

[0054] A method for in-situ spin resonance spectroscopy within a Transmission Electron Microscope ( TEM) comprises the steps :

[0055] - providing a sample , wherein the sample holder holds the sample within the TEM;

[0056] - generating a magnetic bias field by the magnetic field generator, wherein the sample is within the magnetic bias field;

[0057] - irradiating the sample with an electromagnetic excitation signal generated by the electrical circuit ;

[0058] - receiving an electromagnetic response signal from the sample by the electrical circuit ; and

[0059] - detecting a spin resonance of the sample based on the electromagnetic response signal .

[0060] Optionally, the method may comprise the further step :

[0061] - generating a magnetic modulation field, wherein the magnetic modulation field at the location of the sample is preferably essentially parallel , to the magnetic bias field . By means of the modulation field ( i . e . , the magnetic modulation field) and optionally a lock-in detection scheme , the sensitivity of the method may be enhanced and the SNR may be decreased . Lock-in detection schemes are well known in the art in the context of ESR and NMR, for example .

[0062] Optionally, the electron beam of the TEM may be blocked during the in-situ spin resonance spectroscopy . Alternatively, the electron beam may not be blocked . For example , the method may comprise the further steps :

[0063] - irradiating the sample with the electron beam; and

[0064] - detecting a transmitted electron beam and / or a reflected electron beam with the detector .

[0065] By way of example , the disclosure is further explained with respect to some selected embodiments shown in the figures .

[0066] However, these embodiments shall not be considered limiting for the disclosure .

[0067] Fig . 1 schematically shows a nuclear spin and / or electron spin resonance excitation and detection element for in-situ nuclear and / or electron spin resonance spectroscopy in a Transmission Electron Microscope ( TEM) .

[0068] Fig . 2 schematically shows the element of fig . 1 with a vacuum flange for connecting the element with a vacuum chamber of a TEM .

[0069] Fig . 3 schematically shows a partial sectional view of a column 19 of a TEM with a standard sample holder .

[0070] Fig . 4 schematically shows the element and the standard sample holder 20 of fig . 3 in more detail .

[0071] Fig . 5 schematically shows a sample holder comprising a second embodiment of the nuclear spin and / or electron spin resonance excitation and detection element for in-situ nuclear and / or electron spin resonance spectroscopy in the Transmission Electron Microscope ( TEM) .

[0072] Fig . 6 schematically shows the tip of the sample holder of fig . 5 in more detail . Fig. 7 schematically shows a top view of the tip of the sample holder of figures 5 and 6 without a PCB .

[0073] Fig. 8 schematically shows a partial sectional view of the tip of the sample holder of figures 5 and 6 and in particular the PCB.

[0074] Fig. 9 schematically shows another view of the sample holder of figures 5, 6 and 8.

[0075] Fig. 10 schematically shows a partial sectional view of the sample holder of figures 5, 6, 8 and 9.

[0076] Fig. 11 schematically shows a Transmission Electron Microscope (TEM) configured for in-situ electron spin resonance spectroscopy .

[0077] Fig. 12 schematically shows the main components of the setup of f ig . 11.

[0078] Fig. 1 schematically shows a nuclear spin and / or electron spin resonance excitation and detection element 1 for in-situ nuclear and / or electron spin resonance spectroscopy in a Transmission Electron Microscope (TEM) 2 (see fig. 11) . The nuclear spin and / or electron spin resonance excitation and detection element 1 is referred to as element 1, i.e., "element 1" refers to the nuclear spin and / or electron spin resonance excitation and detection element 1 and vice versa. The element 1 comprises a body part 3, wherein the body part 3 is configured for receiving a sample 23 (see figs. 7 or 11, for example) within the body part 3. The element 1 furthermore comprises an electrical circuit 5, in this exemplary embodiment a resonator circuit, configured for emitting an electromagnetic excitation signal and for receiving an electromagnetic response signal from a sample 23within the body part 3. The electrical circuit 5 is arranged within the body part 3 in this example.

[0079] The body part comprises an electron passage 6, wherein the electron passage 6 is configured as a passage for an electron beam 39 (see fig. 11) of a TEM 2. The body part 3 is configured for receiving a sample 23 within the electron passage 6 . An electron beam 39 passing through the electron passage 6 of the body part 3 therefore interacts with a sample 23 within the electron passage 6 . In this example , the electron passage 6 is ef fected by two openings 6A and 6B in the body part 3 . The body part 3 comprises a U-shaped crosssection and is configured for receiving a part of a standard sample holder 20 ( see figs . 3 and 4 ) . Electrons of the electron beam 39 can enter the body part 3 through one of the openings 6A and exit the body part 3 through the other opening 6A. The openings 6A comprise a circular shape in this example . The electron passage 6 comprises a main axis 6B . The main axis 6B intersects a center of each of the openings 6A.

[0080] The electrical circuit 5 is impedance matched to a frequency of the electromagnetic excitation signal and the electromagnetic response signal .

[0081] The electrical circuit 5 comprises an antenna 8 , in this example a micro-strip resonator 9 , wherein the antenna 8 is preferably arranged adj acent to the electron passage 6 .

[0082] The element 1 comprises a printed circuit board ( PCB ) 10 , wherein the PCB 10 comprises the antenna 8 , in this example the micro-strip resonator 9 . The PCB 10 is connected to the body part 3 by means of a fixation screw 10A. The electrical circuit 5 is electrically connected by means of a cable 13 via a cable connector 14 arranged in the PCB 10 .

[0083] Furthermore , the element 1 comprises a modulation coil 11 configured for generating a magnetic modulation field, wherein the magnetic modulation field is essentially parallel to the main axis 6B of the electron passage 6 in at least a section of the electron passage 6 . The modulation coil 11 comprises a main coil axis , which coincides with the main axis 6B of the electron passage 6 .

[0084] The modulation coil 11 is connected to a modulation cable 12 for transmitting a signal to the modulation coil 11 .

[0085] Fig . 2 shows the element 1 with a vacuum flange 15 for connecting the element 1 with a vacuum chamber of the TEM 2 . In intended use , the element 1 is arranged within a vacuum chamber, e . g . , the column, of the TEM 2 . The flange 15 separates an inside of the vacuum chamber of the TEM 2 from the environment. However, by means of the flange 15, components, such as the element 1, may be inserted into the vacuum chamber. In this example, the element 1 comprises an elongated member 16, which is attached to the body part 3. The elongated member 16 is attached to the flange 15. By removing the flange 15, the element 1 can easily be removed from a TEM 2. The flange 15 comprises a modulation cable connector 17 for connecting the modulation cable 12 and a cable connector 18 for connecting the cable 13. Furthermore, the flange 15 comprises a feedthrough for the modulation cable 12 and the cable 13 respectively.

[0086] Fig. 3 schematically shows a partial sectional view of a column 19 of a TEM 2. The element 1 is inserted into the column 19 by means of the flange 15. In addition to the element 1, a standard TEM sample holder 20 is inserted in the column 19. The TEM 2 comprises an electron source to generate an electron beam 39. A main axis of the electron beam 39 (see fig. 11) is aligned vertically in this example. The main axis 6B of the electron passage 6 is also aligned vertical, such that the electron beam 39 can pass through the electron passage 6. The TEM 2 comprises two pole pieces 21.

[0087] Fig. 4 shows the element 1 and the standard sample holder 20 of fig. 3 in more detail. The standard TEM sample holder 20 comprises a standard tip 22, which is configured to hold a sample 23 (see fig. 7 or fig. 11, for example) . The standard tip 22 is inserted in the body part 3, such that a sample 23 that is being held by the standard tip 22 is arranged within the electron passage 6. Therefore, the element 1 does not prevent an interaction of the electron beam 39 of the TEM 2 with the sample 23.

[0088] The standard TEM sample holder 20 and the element 1 are arranged such that the sample 23 is arranged within the electron passage 6. The magnetic modulation field (that is being generated by the modulation coil 11) is essentially parallel to the main axis 6B of the electron passage 6 at least at a location of the sample 23. The magnetic modulation field adds to the magnetic bias field of the TEM 2. The transmission electron microscope 2 for in-situ nuclear and / or electron spin resonance spectroscopy comprises :

[0089] - a sample holder, in this example the standard TEM sample holder 20 , configured to hold the sample 23 ;

[0090] - an electron source for irradiating the sample 23 with an electron beam 39 ;

[0091] -an electron detector unit for detecting the electron beam 39 ;

[0092] - a magnetic field generator for generating a magnetic bias field, wherein the magnetic bias field at the sample 23 is essentially parallel to a main axis of the electron beam 39 . The magnetic field generator comprises the two pole pieces 21 . Furthermore , the TEM 2 comprises the nuclear spin and / or electron spin resonance excitation and detection element 1 , wherein the standard TEM sample holder 20 is configured to hold the sample 23 within the body part 3 of the nuclear spin and / or electron spin resonance excitation and detection element 1 .

[0093] A method for in-situ spin resonance spectroscopy within the Transmission Electron Microscope ( TEM) 2 comprises the steps :

[0094] - providing the sample 23 , wherein the standard TEM sample holder 20 holds the sample 23 within the TEM 2 ;

[0095] - generating a magnetic bias field by the magnetic field generator, wherein the sample 23 is within the magnetic bias field;

[0096] - irradiating the sample 23 with an electromagnetic excitation signal generated by the electrical circuit 5 ;

[0097] - receiving an electromagnetic response signal from the sample by the electrical circuit 5 ; and

[0098] - detecting a spin resonance of the sample 23 based on the electromagnetic response signal .

[0099] In addition, the method comprises the further step :

[0100] - generating a magnetic modulation field, wherein the magnetic modulation field at the location of the sample 23 is essentially parallel , to the magnetic bias field .

[0101] Fig . 5 shows a second embodiment of the nuclear spin and / or electron spin resonance excitation and detection element 1 for in-situ nuclear and / or electron spin resonance spectroscopy in the Transmission Electron Microscope ( TEM) . The element 1 comprises

[0102] - a body part 3 , wherein the body part 3 is configured for receiving a sample 23 on the body part 3 ; and

[0103] - an electrical circuit 5 ( see fig . 5 ) , in this example a resonator circuit , configured for emitting an electromagnetic excitation signal and for receiving an electromagnetic response signal from the sample 23 on the body part 3 , wherein the electrical circuit 5 is arranged on or within the body part 3 .

[0104] In this embodiment , a sample holder 24 for a Transmission Electron Microscope ( TEM) 2 for in-situ nuclear and / or electron spin resonance spectroscopy in the TEM 2 , comprises the nuclear spin and or electron spin resonance excitation and detection element 1 . In this case , the body part 3 is configured to hold the sample 23 , in this example within the electron passage 6 ( details see fig . 6 ) .

[0105] The sample holder 24 comprises a tip 25 , which comprises the element 1 . Furthermore , the sample holder 24 comprises an elongated holder member 26 , for holding the tip 25 . The elongated holder member 26 is attached to a further elongated member 27 . A vacuum O-ring is used to seal the elongated member and the further elongated member 27 . The further elongated member 27 is attached to a further member 28 . The further member 28 is in this exemplary embodiment configured as a flange and may be connected to the column 19 , for example .

[0106] Fig . 6 shows the tip 25 of the sample holder 24 of fig . 5 in more detail . In this exemplary embodiment , the body part 3 comprises a single opening 6A, which forms the electron passage 6 . The PCB 10 comprises the electrical circuit 5 ( see fig . 8 ) . In this example , the electrical circuit comprises a tuning capacitor 29 for tuning the resonance frequency of the electrical circuit 5 . The PCB 10 is attached to the body part 3 by means of a fixation screw 10A. The sample holder 24 comprises a FIB-lamella 30 for receiving and holding the sample 23 . Alternatively to a FIB-lamella, other means for receiving and holding the sample 3 may be used . A FIB ( Focused Ion Beam) lamella is a thin slice of material prepared using a focused ion beam system . The FIB lamella 30 is arranged within the electron passage 6 , such that the electron beam 39 can pass next to the FIB lamella 30 and / or the sample 23 . The FIB- lamella 30 is held in place by means of a retaining ring 31 . The PCB 10 comprises a main plane of extension, which is parallel to the main axis 6B of the electron passage 6 .

[0107] Fig . 7 schematically shows a top view of the tip 25 of the sample holder 24 of figures 5 and 6 without the PCB 10 , such that the sample 23 is visible . A spacer 32 is provided, such that the FIB lamella 30 can be aligned easily . The sample holder 24 comprises a pin 33 to secure the tip 25 to the elongated holder member 26 .

[0108] Fig . 8 schematically shows a partial sectional view of the tip 25 . The antenna 8 is arranged within the electron passage 6 , such that the electrical circuit 5 is configured for emitting an electromagnetic excitation signal and for receiving an electromagnetic response signal from the sample 23 within the body part . The antenna 8 , in this example a micro-strip resonator, is formed by a metallic layer 34 , in this case a copper layer, of the PCB 10 . The modulation coil 11 surrounds the retaining ring 31 and therefore the electron passage 6 .

[0109] Fig . 9 schematically shows another view of the sample holder 24 of fig . 5 . The sample holder 24 comprises a housing 35 for connectors , such as a cable connector or a modulation cable connector 36 and a cable connector 37 . By means of the modulation cable connector 36 , the modulation coil 11 can be connected to a modulation signal generator of the TEM 2 . By means of the cable connector 37 , the electrical circuit 5 can be connected to a radio- frequency signal generator .

[0110] Fig . 10 schematically shows a partial sectional view of the sample holder 24 of fig . 5 . The sample holder 24 comprises a feed-through 38 for the modulation cable 12 and the cable 13 , such that that the modulation coil 11 and the electrical circuit can be connected to external devices by means of the modulation cable 12 and the cable 13 , which are both arranged in the feed-through 38 , and the modulation cable connector 36 and the cable connector 37 respectively . Figures 11 and 12 concern another embodiment of the invention.

[0111] Spin-1 / 2 particle, such as an electron or proton, within a magnetic field exhibits two distinct energy levels EgfS= gePb Bo. The ground state aligns anti-parallel with the field, while the excited state aligns parallel, see Fig. 11. This separation of energy states is described by the Zeeman effect. The energy difference AE=msgePb Bobetween the two states for the electron are a function of the g-factor of the electron gethe Bohr magneton pband the magnetic bias field Bo. Transition between the energy levels is driven by MWs (microwaves) at a resonance frequency of ~ 28 GHz / T for electron spins and at about 1000 times lower frequencies for NMR active spins.

[0112] The example concerns coherent spin manipulation within a TEM 2, combining these quantum technologies and bridging the fields of TEM and ESR / NMR (cf . Philipp Haslinger, Stefan Nimmrichter, and Dennis Ratzel, "Spin Resonance Spectroscopy with an Electron Microscope," (2024) , Quantum Science and Technology (2024) . DOI 10.1088 / 2058-9565 / ad52bc ) see schematics in Fig. 11, which shows an overview of ESR experiment in-situ TEM. A Spin-1 / 2 particle is placed in the Bomagnetic field, generated by the pole pieces 21 (of a magnetic field generator) of a TEM 2. Inset on the right side shows a Zeeman energy-level scheme. Transition between the Zeeman levels is induced by electromagnetic field of the appropriate frequency L) / Bo» 28 GHz / T for electron spins and at about 1000 times lower frequencies for NMR active spins, resulting in MW absorption and ESR signal.

[0113] In order to record ESR spectra with high spin sensitivity a miniaturized impedance matched microwave circuit (i.e., an electrical circuit 5) on a TEM sample holder 24 was implemented. While commercial ESR spectrometer are mainly optimized for sample volumes of 1 mm3to 1 cm3, with spin sensitives of 109- 1011spins / Hz1 / 2, such microcoil geometries have shown outstanding sensitivities down to ~ 108spins / Hz1 / 2at 300 K and 50 GHz for < 1 mm3samples (see, for example G Boero, M Bouterfas, C Massin, F. Vincent, P. A. Besse, R. S. Popovic, and A. Schweiger, "Electron-spin resonance probe based on a 100 m planar microcoil," Review of Scientific Instruments 74, 4794-4798 (2003) . Or Alessandro V Matheoud, Gabriele Gualco, Minki Jeong, et al., "Single-chip electron spin resonance de- tectors operating at 50 GHz, 92 GHz, and 146 GHz," Journal of Magnetic Resonance 278, 113-121 (2017) .) . The strong magnetic field (adjustable from almost 0 to ~1.7 T) within the TEM pole piece at the specimen region (i.e., the location of the sample 23) provides the needed Bofield for spin polarisation .

[0114] For the investigation of the electron spin properties within a TEM 2 (in this case a "FEI F20") , a TEM sample holder 24 (Fig. 12A) was implemented. In addition, an ESR setup similar to Boero, G., et al. "Electron-spin resonance probe based on a 100 pm planar microcoil." Review of scientific instruments 74.11 (2003) : 4794-4798 was implemented, see fig. 12B. Note that ERR (electron paramagnetic resonance) is a synonym for ESR. For the spin state polarization, the magnetic field (i.e., the magnetic bias field) of the TEM pole pieces 21, operating in low magnification mode, resulting in Bo~ 170 mT field at the specimen (i.e., the sample 23) . This lens excitation serves a dual purpose: facilitating efficient acquisition of ESR spectra and enabling extended camera lengths in diffraction for the observation of small beam deflections, paving the way for future investigations with a highly controlled beam at the nanoscale. The micro-coil antenna 8 on a printed circuit board (RGB 10) is impedance matched to Do = 4.5 GHz, allowing efficient specimen excitation and inductive ESR signal detection, see Fig. 12b. The sample 23 is placed in a close proximity to the centre of the micro-coil to ensure optimized coupling to the antenna 8, but also to allow for free space access for electron microscopic examinations, see Fig. 12b. In this exemplary setup, a Rohde & Schwarz SMB100B was used as a MW generator. The MW (~5 GHz) are guided to the TEM sample holder via vacuum feedthroughs to break the air-to-vacuum barrier. For low- noise ESR investigations, a miniaturized modulation coil on the sample holder generates a B0-field-modulated ESR signal (5 GHz + 100 kHz) . The signal is then routed out of the TEM 2, decoupled from the mainline via directional coupler, amplified, filtered, and mixed down to modulation frequency (100 kHz) . When phase sensitive detection is used, only signals of the same modulation frequency can be detected. Hence, final data acquisition is performed on a lock-in amplifier (in this case an "SR810") , which generates in-phase and quadrature signals often denoted as I and Q, respectively. By sweeping the MW frequency across the resonance, an ESR spectrum is obtained, representing the first derivative of ESR absorption due to field modulation. Moreover, by setting the MW phase difference on the mixer, it is also possible to record an ESR dispersion signal and its derivative, which are akin to the first and second derivatives of the ESR absorption signal, respectively (cf. Jan Talpe and Lieven Van Gerven, "Dispersion, a most useful tool in paramagnetic resonance," Physical Review 145, 718 (1966) ) . Figure 12A and 12B schematically show the ESR microwave components and the TEM sample holder 24 as well as the PCB 10 (for details concerning the sample holder 24, see fig. 6, for example) .

[0115] The in-situ ESR experiment configuration according to figures 12A and 12B: Microwaves (5 GHz) and RE modulation signal (100 kHz) for lock-in amplification scheme are fed onto the TEM sample holder 24 from an ESR setup outside the TEM 2 via vacuum feedthroughs. Impedance matched MW micro-coil antenna 8 mounted on a printed circuit board (PCB 10) generates an inplane Bx magnetic field, efficiently exciting the sample positioned at FIB lift-out-grid in close proximity to the coil center. The modulation coil varies the out-of-plane Bomagnetic field. Bx and Boare orthogonal to each other, in this exemplary embodiment. Back-reflected MW (5 GHz) together with the modulated ESR signal from the specimen (5 GHz ± 100 kHz) are guided out of the TEM sample holder 24, filtered, amplified, mixed down to the modulation frequency (100 kHz) and detected via a lock-in amplifier. Overall, this setup enables optimized measurements on miniaturized specimen by employing inductive coupling as well as sample excitation for future TEM spin readout protocols.

[0116] The sensitivity of the setup can be easily improved by increasing the bias magnetic field Boto ~ 1.7 T, which is the upper threshold for the FEI F20 TEM, resulting in a transition frequency of Do = 50 GHz and a corresponding improvement oc u02 of the SNR by a factor of 100. Also cryogenic temperatures are beneficial, as are often used in cryo-TEM.

[0117] A temperature reduction from room temperate to 77 K (LN2) or 4 K (LHe) leads to a spin polarisation gain oc T of 4 and 75, respectively, as well as significant improvement oc T of the thermal readout noise (Johnson-Nyquist noise) . Maximizing both values leads to a spin polarisation of ~ 35% and a spin sensitivity of better than ~2-105spins / Hz1 / 2, (G. Boero, G.

[0118] Gualco, R. Lisowski, et al., "Room temperature strong coupling between a microwave oscillator and an ensemble of electron spins," Journal of Magnetic Resonance 231, 133-140 (2013) ) sufficient to even investigate nanometer-scaled sample sizes.

[0119] Similar ESR investigations in a TEM can also be performed in combination with an external ESR setup, which is attached to an additional flange on the octagon next to the sample holder in the form of an add-on. This brings the great advantage that ESR investigations are not limited to a special MW sample holder, but can be carried out on different specially optimized sample holders (cryo, liquid cell, gas cell etc.) .

Claims

Claims1. A nuclear spin and / or electron spin resonance excitation and detection element (1) for in-situ nuclear and / or electron spin resonance spectroscopy in a Transmission Electron Microscope (TEM) comprising:- a body part (3) , wherein the body part (3) is configured for receiving a sample (23) on or within the body part (3) ; characterized by- an electrical circuit (5) , preferably a resonator circuit, configured for emitting an electromagnetic excitation signal and for receiving an electromagnetic response signal from a sample (23) on or within the body part (3) , wherein the electrical circuit (5) is arranged on or within the body part (3) .

2. Element according to claim 1, characterized in that the body part (3) comprises an electron passage (6) , wherein the electron passage (6) is configured as a passage for an electron beam (39) of a TEM (2) , wherein the body part (3) is configured for receiving a sample (23) within the electron passage ( 6 ) .

3. Element according to claim 1 or claim 2, characterized in that the electrical circuit (5) is impedance matched to a frequency of the electromagnetic excitation signal and / or the electromagnetic response signal.

4. Element (1) according to anyone of claims 1 to 3, wherein the electrical circuit (5) comprises an antenna (8) , in particular a micro-strip resonator, wherein the antenna (8) is preferably arranged adjacent to or within the electron passage (6) .

5. Element according to claim 4, characterized by a printed circuit board (PCB) (10) , wherein the PCB (10) comprises the antenna ( 8 ) .

6. Element according to anyone of claims 1 to 5, characterized by- a modulation coil (11) configured for generating a magnetic modulation field, wherein the magnetic modulationfield is preferably essentially parallel to a main axis of the electron passage in at least a section of the electron passage (6) .

7. Element according to claim 6, characterized by a sample (23) arranged within the electron passage (6) , wherein the magnetic modulation field is essentially parallel, to the main axis of the electron passage at least at a location of the s amp 1 e (23) .

8. A sample holder (24) for a Transmission Electron Microscope (TEM) (2) for in-situ nuclear and / or electron spin resonance spectroscopy in a TEM (2) , characterized by the nuclear spin and or electron spin resonance excitation and detection element (1) according to any one of the previous claims, wherein the body part (3) is configured to hold a sample (23) , preferably within the electron passage (6) .

9. A transmission electron microscope (2) for in-situ nuclear and / or electron spin resonance spectroscopy comprising:- a sample holder (24) configured to hold a sample (23) ;- an electron source for irradiating the sample (23) with an electron beam (39) ;-an electron detector unit for detecting the electron beam (39) ;- a magnetic field generator for generating a magnetic bias field, wherein the magnetic bias field at the sample (23) is essentially parallel to a main axis of the electron beam (39) , characterized by a nuclear spin and / or electron spin resonance excitation and detection element (1) according to anyone of claims 1 to 7, wherein the sample holder (24) is configured to hold the sample (23) on or within the body part (3) of the nuclear spin and / or electron spin resonance excitation and detection element ( 1 ) .

10. Transmission electron microscope according to claim 9, characterized by a nuclear spin and / or electron spin resonance excitation and detection element (1) according to anyone of claims 2 to 7, wherein a main axis (6B) of the electronpassage (6) is essentially parallel to the main axis of the electron beam (39) , wherein the electron beam (39) is configured to pass through the electron passage (6) , wherein the sample holder (24) is configured to hold the sample (23) within the electron passage (6) .

11. Transmission electron microscope (2) according to claim 9 or claim 10, characterized by a radio-frequency signal generator for generating a radio frequency signal, wherein the radio-frequency signal generator is connected to the electrical circuit, such that the electrical circuit (5) receives the radio frequency signal.

12. Transmission electron microscope (2) according to anyone of claims 9 to 11 with a spin resonance excitation and detection element according to claim 6 or claim 7, characterized by a modulation signal generator for generating a modulation signal, wherein the modulation signal generator is connected to the modulation coil (11) , such that the modulation coil (11) receives the modulation signal.

13. Transmission electron microscope (2) according to anyone of claims 9 to 12, characterized in that the sample holder (24) comprises the spin resonance excitation and detection element ( 1 ) .

14. Method for in-situ spin resonance spectroscopy within a Transmission Electron Microscope (TEM) (2) according to anyone of claims 9 to 13 with the steps:- providing a sample (23) , wherein the sample holder (24) holds the sample (23) within the TEM;- generating a magnetic bias field by the magnetic field generator, wherein the sample (23) is within the magnetic bias field;- irradiating the sample (23) with an electromagnetic excitation signal generated by the electrical circuit (5) ;- receiving an electromagnetic response signal from the sample (23) by the electrical circuit (5) ; and- detecting a spin resonance of the sample (5) based on the electromagnetic response signal.

15. Method for in-situ spin resonance spectroscopy according to claim 14 with a spin resonance excitation and detection element (1) according to claim 6, with the further step:- generating a magnetic modulation field, wherein the magnetic modulation field at the location of the sample (23) is preferably essentially parallel, to the magnetic bias field .

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