56 results about "Magneto-optic Kerr effect" patented technology

The invention belongs to the optical technical field, in particular to a measuring device of magneto-optical kerr effect on longitudinal surface of a large field. The device consists of an electromagnet, a program control magnet power supply, a light path system and an operation control system (PC), wherein, the light path system subsequently consists of a semiconductor laser, a polarizing prism, a half transparent and half reflecting prism, a polarization detecting prism, a photodetector, a convex lens, a sample holder, an aperture, another polarization detecting prism, a long focal length convex lens and another photodetector; a magnetic filed for measurement is provided by the electromagnet which can provide a magnetic filed up to 1.5 tesla when the magnetic pole spacing is 4cm. The invention uses a converging convex lens to effectively expand the incident angle and the reflection angle of the light on the surface of the a sample, overcome the restriction of the magnetic pole spacing to the incident angle of the laser and enhance the magneto-optical kerr signal intensity on the longitudinal surface. The invention makes measurement of the high-coercivity magnetic film by the magneto-optical kerr effect possible.

The invention discloses a multifunctional reflection-type magneto-optic spectrum measuring system which uses a super-continuous white light source, a grating monochromator, a plurality of polarized lenses, a photoelastic modulator, a broad band 1 / 4 and 1 / 2 wave plate, a non-polarization beam splitter (NPBS), a single-ended differential detector and an OXFORD low-temperature superconducting magnet system to form a spectrum detection system with a flexible and variable structure. The invention can realize the measurement of reflection-type magnetic circular dichroism (MCD), polar magneto-optical Kerr effect, polarized reflection spectrum and magnetic wire magnetic linear dichroism (MLD) on the same light path. The system has high sensitivity and can be used for fields, such as basic physics research, material characteristic analysis, light polarization modulation communication and the like.

The invention discloses a system for measuring linear and non-linear magneto-optical Kerr rotation, which comprises an ultra-short pulse laser, a helium-based closed-cycle refrigerator, an electromagnet, a laser-pumping optical path, a laser-detection optical path, a linear Kerr signal collection optical path, a non-linear Kerr signal collection optical path, a lock-in amplifier signal collection system and a laser spot monitoring system, wherein the helium-based closed-cycle refrigerator is provided with optical windows and used for controlling the temperature of a sample; the size of the air gap and the magnitude of the magnetic field of the electromagnet are adjustable; the laser-pumping optical path is used for leading in the laser inputted by the ultra-short pulse laser and focusing the laser on the surface of the sample inside the refrigerating head, so as to excite the sample; the polarization plane of the laser-detection optical path rotates after a beam of laser outputted by the ultra-short pulse laser is reflected by the sample; the linear Kerr signal collection optical path is used for collecting the base-frequency signal of the detection laser; the non-linear Kerr signal collection optical path is used for receiving the frequency-doubled signal of the detection laser; the lock-in amplifier signal collection system is used for filtering and amplifying the signals and transmitting the signals to a computer for processing; and the laser spot monitoring system is used for accurately controlling the overlap ratio of the pumped beam laser spot and the detected beam laser sport. The system provided by the invention for measuring the linear and non-linear magneto-optical Kerr rotation is capable of simultaneously adjusting the temperature and the intensity of the magnetic field applied to the sample and achieving the measurement of the linear and non-linear magneto-optical Kerr effect on a temperature-variable steady-state basis or a time-resolved dynamic basis.

The invention discloses an anti-counterfeiting component and an anti-counterfeiting product, wherein the anti-counterfeiting component comprises a base layer. A magneto-optical information layer is arranged on the base layer, machine-readable safety information based on a magneto-optical characteristic is loaded on the magneto-optical information layer. The magneto-optical characteristic comprises a magneto-optical faraday effect or a magneto-optical Kerr effect. The anti-counterfeiting product comprises an object which is provided with the anti-counterfeiting component. The anti-counterfeiting component is adhered to the object through a first adhesive layer and / or a second adhesive layer. An embodiment of the anti-counterfeiting component and the anti-counterfeiting product can improve anti-counterfeiting performance of the anti-counterfeiting component and safety of the anti-counterfeiting product.

The invention relates to a device and a method for detecting a force thermal magnetic coupling action of a ferromagnetic thin film, and belongs to the technical fields of engineering materials, structure deformation and mechanical experiments. The device comprises a ferromagnetic thin film uneven stress measuring optical circuit, a film magnetic hystersis loop measuring optical circuit, a Helmholtz coil and a power supply thereof, a test piece heating table, a thermocoupler, a force loading structure and an adjusting bracket. The film uneven stress measuring optical circuit comprises a laser, a beam expander, a spectroscope, a reflector, a raster, a lens, a filtering screen and a CCD camera; and the film magnetic hystersis loop measuring optical circuit comprises a laser, a beam expander, a reflector, a polarizer, a polarization analyzer and a photodetector. The method utilizes the Helmholtz coil to provide an even magnetic field for the ferromagnetic thin film, utilizes the test piece heating table to heat the film, utilizes the force loading structure to carry out force loading on the film, utilizes shearing interference to measure uneven curvature of the surface of the film and further obtain the stress of the film through the curvature, and utilizes Kerr magnetooptical effect on the surface of the ferromagnetic thin film to measure a magnetic hystersis loop of the film.

A spatially resolved magneto-optic Kerr effect measurement device comprises an optical path system, a three-dimensional piezoelectric sample stage, and a current source control unit. The system can carry out poloidal or longitudinal Kerr signal scanning measurement of a single point quickly under a changing magnetic field, and can carry out Kerr signal measurement of the points in a region in a mode of matrix scanning under a fixed magnetic field. With the spatially resolved magneto-optic Kerr effect measurement device, the static magnetic domain and dynamic magnetic domain of a region can be measured precisely. Moreover, the magnetic domain structure of a whole region to be measured can be observed under a fixed magnetic field.

The invention discloses a spectrum magneto-optical ellipsometry analysis device of a rotary compensator as well as application thereof. The spectrum magneto-optical ellipsometry analysis device comprises a light source module, a light path module, a magnetic field module, a sample table, a motor control module and a detection and analysis module, the light path module comprises a collimating lens,a polarizer, a compensator and a polarization analyzer, the detection and analysis module comprises a computer and a detector, the collimating lens, the polarizer, the compensator, the sample table,the polarization analyzer and the detector are sequentially arranged along a light path direction, the polarizer and the compensator are located in an incidence light path, the polarization analyzer is located in an emergence light path, and the incidence light path and the emergence light path are located at the two sides of the sample table and respectively keep an included angle Phi with normalof the sample table. The device disclosed by the invention can represent optical and magnetic parameters of a magnetic film material under longitudinal or poloidal magneto-optical Kerr effect, can obtain thickness, optical parameters and magnetic parameters of a magnetic film sample during one test and is relatively high in automation degree.

The invention belongs to the technical field of physical measurement, and in particular relates to a magneto-optic Kerr effect and magnetocrystalline anisotropy field measurement system and a measurement method. The measurement system comprises a magnet control part and a laser detection part. The magnet control part mainly comprises a magnet bracket, power supplies, an ADDA (analog-digital and digital-analog) card and a computer, wherein the computer respectively controls the size and the direction of output current of the two power supplies through the ADDA card, and respectively controls the size and the direction of magnetic fields so as to obtain a required resultant magnetic field; and the laser detection part is composed of a laser device, a polarizer, a polarization analyzer, a photoelectric detector, an ADDA card and a computer, wherein laser emitted by the laser device is projected to the photoelectric detector after being filtered by the polarizer and the polarization analyzer, signals are transmitted to the computer after being converted by the ADDA card, and then Kerr signals of a detection point are obtained. According to the measurement system and the measurement method, the mechanical vibration can be eliminated, the noise in the measurement can be reduced, the accuracy of the measurement can be increased, and magnetic signals and the magnetocrystalline anisotropy field of a sample can be accurately and efficiently obtained.

An online detection method for magnetoelasticity performance of thin-ferromagnetic-film, which belongs to the field of engineering materials, structure deformation, and mechanical test. The device implementing the method of the invention comprises a thin-ferromagnetic-film non-uniform stress measuring light path and a film hysteresis loop measuring light path, wherein, the film non-uniform stress measuring light path comprises a laser, a beam expander, a grating, a lens, a filter screen, and a CCD camera; and the film hysteresis loop measuring light path comprises a laser, a beam expander, a polarizer, an analyzer, and a photodetector. The method of the invention comprises the steps of measuring non-uniform curvature of the thin-ferromagnetic-film surface by shearing interferometer to obtain the non-uniform stress in film, and measuring the hysteresis loop of the film by using magnetooptic Kerr effect of the thin-ferromagnetic-film surface. The method can simultaneously online measure the non-uniform stress and the hysteresis loop of thin-ferromagnetic-film, so as to provide experimental basis for the research on magnetoelasticity coupling behavior of the thin-ferromagnetic-film.

An apparatus and method of testing a magnetic medium at temperatures of interest is disclosed. Properties of the magnetic medium are determined by focusing light from a source of polarized light on a magnetic surface of the magnetic medium; measuring polarization of resulting reflected light due to the magneto-optical Kerr effect, using, for example a measuring subsystem; and varying the light source to heat the magnetic material where incident to pre-defined temperatures, thereby allowing determination of the magnetic properties using the magneto-optical Kerr effect at said pre-defined temperatures.

The invention discloses a device and a method for detecting the force electromagnetic coupling behavior of a giant magneto resistive film, and belongs to the technical field of engineering materials, structural deformation, mechanics experiment and electrical experiment. The device comprises a magnetic field generator, a giant magneto resistive film hysteresis loop measurement optical path, a film stress measurement optical path, and a film resistance probe tester. The giant magneto resistive film hysteresis loop measurement optical path comprises a laser, diaphragms, reflectors, a polarizer, an analyzer, a lens and a photoelectric detector; and the film stress measurement optical path comprises a laser, a spatial filter, a calibrator, reflectors, and a charge couple device (CCD) camera. A uniform magnetic field is provided by the magnetic field generator; the hysteresis loop is measured according to a magneto-optic Kerr effect; curvature of the surface of the film is measured by a multi-beam optical stress sensitivity technology; the stress of the film is obtained according to the relation expression of the curvature and the stress; the resistivity of a film material is measured by the film resistance probe tester; and coupling relational expressions of the resistance of the giant magneto resistive film and the magnetic induction density and stress of the film can be obtained finally.

The invention belongs to the technical field of magnetism test, in particular to a comprehensive test system for magnetism of a material. The system integrates four discrete magnetics test systems, namely a magnetic balance, magnetostriction, a surface magneto-optic Kerr effect and a vibrating specimen magnetometer, uses the same electromagnet, the same testing platform and the same set of control and signal processing system and can be conveniently switched among four different test methods. Therefore, the system reduces expense for buying various instruments and test cost, simplifies a signal processing step and can be widely applied to the comprehensive magnetism tests for various materials.

A method of amplifying a magneto-optical Kerr effect by using photon crystal structures, and a photon crystal having an amplified magneto-optical Kerr effect, and a method of fabricating the photon crystal. The method of amplifying a magneto-optical Kerr effect by using photon crystal structures includes amplifying the magneto-optical Kerr effect by fabricating a magnetic photon crystal including a crystal magnet and using a periodically-structured surface of the crystal magnet.

The invention provides a device and a method for carrying out a spectrum-type magneto-optical Kerr effect test by using a spectrograph. The device comprises a white-light light source, a collimating lens, a polarizer, two diaphragms, an electromagnet, a sample platform, a polarization analyzer, a collecting lens, an optical fiber coupling device, a spectrograph and a PC (Personal Computer) machine. The device is characterized in that the white-light light source is connected with the collimating lens by an optical fiber and white light is output after the white-light light source is focused by the collimating lens; the polarizer, the two diaphragms, the polarization analyzer, the collecting lens, the optical fiber coupling device and the spectrograph are arrayed behind the collimating lens along a light path sequentially; a quarter-wave plate needs to be arranged behind the polarization analyzer and in front of the collecting lens when the ellipsometry rate is measured and the quarter-wave plate does not need to be placed when a magneto-optical deflection angle is measured; the sample platform is arranged between the two diaphragms and the sample platform is located in the middle of the electromagnet; the optical fiber coupling device is connected with the spectrograph by the optical fiber; the output end of the spectrograph is connected with the PC machine; the spectrograph is controlled by the PC machine through programming and a result is output. The system has a simple light path, low in cost and high in data precision; a spectrum curve of the magneto-optical deflection angle can be formed.

Apparatus and methods are disclosed that enable writing data on, and reading data of, multi-state elements having greater than two states. The elements may be made of magnetoplastic and / or magnetoelastic materials, including, for example, magnetic shape-memory alloy or other materials that couple magnetic and crystallographic states. The writing process is preferably conducted through the application of a magnetic field and / or a mechanical action. The reading process is preferably conducted through atomic-force microscopy, magnetic-force microscopy, spin-polarized electrons, magneto-optical Kerr effect, optical interferometry or other methods, or other methods / effects. The multifunctionality (crystallographic, magnetic, and shape states each representing a functionality) of the multi-state elements allows for simultaneous operations including read&write, sense&indicate, and sense&control. Embodiments of the invention may be used, for example, for storing, modifying, and accessing data for device, sensor, actuator, logic and memory applications. Embodiments may be particularly effective for non-volatile memory or other read&write, sense&indicate, and / or sense&control functions in computer or other applications; such simultaneous operation of two (or more) of said multiple functionalities open new pathways for miniaturization of devices.

The invention discloses a backlight module and a display device. The backlight module comprises a brightening film, a diffusion plate and a magnetic reflective sheet, wherein the brightening film is used for allowing linearly polarized light in the first direction to penetrate through and reflecting linearly polarized light in the second direction perpendicular to the first direction; the magnetic reflective sheet is used for transforming the linearly polarized light reflected by the brightening film into elliptically polarized light by the magneto-optical Kerr effect; linearly polarized light component in the first direction in the elliptically polarized light reflected by the magnetic reflective sheet can penetrate through the brightening film, linearly polarized light component in the second direction is reflected again to the magnetic reflective sheet and is transformed into the elliptically polarized light, the operation cycles continuously, the ratio of the linearly polarized light in the direction of the brightening film is increased, utilization rate of backlight is increased, and brightness of a liquid crystal display is improved.

The invention provides a method for measuring a flexible magnetic film saturated magnetostriction coefficient. The method comprises the steps of: adopting a nonmagnetic mould which is made of a nonmagnetic material and has a fixed radius of curvature to generate strain on a flexible magnetic film so as to obtain a stress difference deltasigma between the condition of applied stress and the condition of no stress; then utilizing a magneto-optic kerr effect testing system to measure variable quantity deltaHK of an anisotropy field of the flexible magnetic film sample at the presence of strain and at the absence of the strain; and directly calculating to obtain a saturated magnetostriction coefficient gammas of the flexible magnetic film through a saturated magnetostriction coefficient formula gammas=deltaHkMs / (3deltasigma). Compared with the conventional magnetostriction coefficient measurement method of the magnetic film, the method for measuring the flexible magnetic film saturated magnetostriction coefficient, disclosed by the invention, has the advantages of high measurement precision, simple and practicable performances, low cost and good application foreground.

The invention relates to the field of optical current sensors, and particularly relates to a magneto optical current transducer, which comprises a laser, a ring coupler, a polarization-maintaining transmission optical fiber, a one-to-two optical fiber branching device, a magneto optical module, a ferromagnetic concentrator ring, and a differential demodulator; and the magneto optical module comprises a collimator, a polarizer, a lambda / 4 waveplate, rectangular optical glass and magnetized bodies at two ends. According to the magneto optical current transducer, based on poloidal surface magneto optical Kerr effects, the differential demodulator is matched, the magnitude of power frequency alternating current in a transmission line is indirectly detected through detecting the relative value of magnetized surface reflected light polarization deflection angles, and the detection precision and the device stability are improved.

A magnetic testing apparatus includes a magnet assembly with a sample path extending through the magnet assembly. The magnetic field produced by the magnet assembly defines a known, varying magnetic field profile along the sample path. A sample is moved along sample path such that the sample portion is subjected to a predetermined magnetic field ramp or magnetic field profile during a measurement period. A measurement arrangement is also provided to measure one or more properties of the sample during the measurement period, in order to test sample properties at a plurality of different magnetic fields. The apparatus may be particularly suited to magneto-optical measurements, including Magneto-Optical Kerr Effect measurements. The apparatus may be used for testing of hard disk platters.

The invention is applicable to the field of nondestructive testing, and provides a device for studying the relationship between stress and magnetic memory effect. The device comprises a fixed platform. A ferromagnetic device to be tested is mounted on the fixed platform. The fixed platform can stretch and compress the ferromagnetic device to be tested. The device further comprises a laser transmitter, a polarizer, an optical focusing lens component, an analyzer, and a photosensitive element. Laser emitted by the laser transmitter is changed into linearly polarized laser after passing through the polarizer. The linearly polarized laser, after passing through the optical focusing lens component, focuses and shines on the surface of the ferromagnetic device to be tested. After the linearly polarized laser is reflected, reflected laser focuses through the optical focusing lens component, passes through the analyzer, and shines on the photosensitive element. By making use of the advantages of the magneto-optical Kerr effect, the device can be used to study the relationship between stress and magnetic memory effect in ferromagnetic materials, and can be applied to crack detection. The device of the invention has strong anti-interference performance, and avoids systematic error caused by indirect measurement using a flexible substrate and a magnetic film.

A laser beam is directed through a transmissive axicon telescope or a reflective axicon telescope such as in a magneto-optic Kerr effect metrology system. With the transmissive axicon telescope, a Gaussian beam profile is directed through a first axicon lens and a second axicon lens. The first axicon lens and second axicon lens transfer the Gaussian beam profile of the laser beam to a hollowed laser ring. The laser beam with a hollowed laser ring can be directed through a Schwarzschild reflective objective. With the reflective axicon telescope, the laser beam is directed through two conical mirrors that are fully reflective. One of the conical mirrors defines a central hole that the laser beam passes through.

The invention belongs to the technical field of physical measurement, and particularly provides a method for measuring antiferromagnetic domain distribution by using the magneto-optic Kerr effect. A magneto-optic Kerr microscope having the function of acquiring the digital image is used. The measurement process comprises the steps of data acquisition: a polarizer acting as a polarization analyzeris controlled to deviate the same angle to the clockwise or anticlockwise direction in the extinction position so as to acquire two images of the sample surface; data analysis: firstly the two acquired images are blurred and all the magnetic domain information is removed and only the uneven light intensity information of the sample surface is reserved and then the contribution of the uneven lightintensity is eliminated out of the two original images so as to obtain the mixed signals of the shape and magnetic domain information of the two samples; and then subtraction and other processing areperformed so as to obtain the antiferromagnetic domain distribution of the sample surface. The method has low cost and provides multiple possible directions for the research of the antiferromagnetic materials.

The invention discloses a method for adjusting the damping factor of a CoFeB film through changing the growth sequence of MgO / CoFeB / Ta. The structure is better in perpendicular anisotropy and is goodin adjustability of the damping factor, so the material is a key material which can be used for generating an MRAM (Magnetic Random Access Memory) device. The magnetron sputtering is used for growinga Ta / CoFeB / MgO superthin film and an MgO / CoFeB / Ta superthin film, and a TRMOKE (Time Resolved Magneto-Optical Kerr Effect) is used for testing the damping factor of the material. The damping factor alpha of Ta / CoFeB / MgO is 0.017, and the damping factor of MgO / CoFeB / Ta is 0.027. Because the change of the damping factor is big, the material is very suitable for the increase of the reading and writing speed of the MRAM. The structure of a sample in the invention sequentially consists of a substrate, a buffering layer, a magnetic layer, and a coverage layer. The repetition frequency of femtosecondpulse laser is 1000Hz, the pulse width is 50fs, and the pumping power density is 3.54mJ / cm2.

The invention relates to a highly-doped ZnO:Co magnetic semiconductor film material and a preparation method thereof. The structural formula of the highly-doped ZnO:Co magnetic semiconductor film material is Zn1-xCoxO, wherein x=0.2-0.45. The Zn1-xCoxO magnetic semiconductor material with a monocrystal single-phase wurtzite lattice structure is prepared by an oxygen molecule beam epitaxy preparation method in a low-temperature ultralow-oxygen atmospheric pressure condition, and the maximum Co metal solid solubility reaches 45%. A Zn1-xCoxO magnetic semiconductor prepared by the method has ultrahigh room temperature ferromagnetism, maximum saturation magnetization of 530emu / cm<3>, maximum average atomic magnetic moment of 1.68muB / Co and a great room-temperature magneto-optic Kerr effect. The prepared Zn1-xCoxO magnetic semiconductor material can be used for spinning electronic devices.

The invention relates to the field of high-pressure physical experiments and material physical property measurement, in particular to a high-pressure sample testing table used for measurement of the magneto-optical Kerr effect. Buttress threads specially designed are arranged on the inner side surfaces of sleeves and the outer side surfaces of displacement tubes respectively, and buttress threadsare adopted by the mobile structures of pressing devices used for pressing tungsten carbide anvil cells, so that thermodynamic deformation of optical fibers and the pressing devices of the anvil cellsis relatively consistent in low-temperature environments, and then optical path adjusting is more precise; a conducting glass electrode board with thickness of 100 micrometers is made from indium tinoxide, and the surface of the conducting glass electrode board is coated with a silylene coating; a sample is located at the center of a teflon ring, the outer ring of the teflon ring is sleeved witha stainless steel ring, the outer ring of the stainless steel ring is sleeved with an aluminum gasket composed of an upper portion and a lower portion, axial through holes are formed in the stainlesssteel ring and the teflon ring, a copper thread is placed between the upper portion and the lower portion of the aluminum gasket, a gold thread penetrates the axial through holes of the stainless steel ring and the teflon ring, one end of the gold thread is connected with the sample, the other end of the gold thread is connected with the copper thread, and particles supporting the gold thread arearranged in the area between the teflon ring and the sample.

The invention relates to a method for measuring the physical property of a magneto-optical dielectric film under a low-temperature and high-pressure condition for high-pressure physical experiments and material physical property measurement. A sample is placed in a Teflon ring. A ruby sheet is placed beside the sample. One end of a gold wire is connected with the sample via silver glue. A liquid pressure medium is continuously added to the Teflon ring. A pressing device applies pressure to an anvil. A displacement tube and a screw are adjusted so that the relative position between an optical fiber and a gradual change refractive index lens and between an optical fiber and a silicon carbide supporting table meets an optical fiber Transmission requirement. Pressure is measured by using a ruby fluorescence method. The dielectric constant of the sample is measured. A current wire is connected to a dielectric constant meter and the dielectric constants of the sample under various anvil pressure conditions are recorded. A magnetic field is applied to the sample. A laser emitted from a laser device irradiates the surface of the sample after passing through a polarizer. The light reflectedfrom the sample surface passes through an analyzer and enters a photoelectric detector to measure a magneto-optical Kerr effect and obtain the magnetization state of the sample under different pressure conditions.