Spin wave dispersion spectrum testing method and system based on microwave method to achieve wave vector resolution

Abstract

The present invention discloses a spin wave dispersion spectrum test method and system based on microwave method to achieve wave vector resolution, and relates to the field of spin wave detection technology. A microwave source module emits microwaves of different frequencies to a sample to be tested; a uniform magnetic field module provides a uniform magnetic field of different magnetic field strengths to the sample to be tested; the sample to be tested generates spin wave resonance under the uniform magnetic field and microwave excitation; the amplitude of the microwave changes under the action of the spin wave resonance, and the diode power detector converts the changed microwave signal into a first voltage signal; the phase-locked amplifier module collects the first voltage signal; the data processing module performs three-dimensional drawing processing on the electromagnetic wave frequency, uniform magnetic field strength, and the first voltage signal to obtain a spin wave dispersion relationship diagram, and further obtains the data of the change of the internal standing wave with the wave vector under different magnetic fields. The present invention realizes for the first time a spin wave dispersion spectrum test method with wave vector resolution based on the microwave method, and improves the wave vector resolution efficiency and accuracy of the spin wave dispersion spectrum.

Description

Technical Field

[0001] The present invention relates to the technical field of spin wave detection, and in particular to a spin wave dispersion spectrum testing method and system for realizing wave vector resolution based on a microwave method. Background Art

[0002] The main parameters of spin waves are amplitude, frequency, phase and wave vector. The eigenfrequency of spin waves in magnetic media is not only related to the effective magnetic field and exchange interaction, but also to the wave vector. Therefore, the wave vector-resolved dispersion relation is very important for studying the propagation characteristics of spin waves.

[0003] Experimentally, spin wave modes can be studied using the excitation method or the inelastic scattering method. Using ultrafast lasers or microwaves to excite spin waves, vertical standing wave modes with fixed wave vectors can be detected. In continuous films, for magnetostatic long-wave spin waves with wave vectors in the plane, only Brillouin light scatterers using optical inelastic scattering methods can achieve wave vector-resolved spin wave dispersion spectrum testing. There are also a few works that have achieved the testing of a few standing wave modes of magnetostatic surface waves by photolithography into micron-scale stripes.

[0004] Due to the development of phase-locked ferromagnetic resonance technology in recent years, microwave methods have become increasingly sensitive to high-frequency dynamics testing in thin films. Through special sample processing and design, it has become possible to use microwave methods to perform magnetostatic surface wave dispersion testing. Since the Brillouin light scattering instrument uses internal thermal excitation of the material to generate spin waves, and uses the wave vector of the laser to achieve wave vector resolution of the spin wave spectrum, there is a problem of low efficiency. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a spin wave dispersion spectrum testing method and system based on the microwave method to achieve wave vector resolution, so as to improve the wave vector resolution efficiency of the spin wave spectrum and improve the accuracy of the wave vector resolution of the spin wave spectrum.

[0006] To achieve the above purpose, the embodiment of the present invention provides the following solution:

[0007] A spin wave dispersion spectrum testing system for realizing wave vector resolution based on microwave method, comprising:

[0008] A microwave source module, used for emitting microwaves of different frequencies to the sample to be tested through the coplanar waveguide plate of the test fixture according to the first control signal;

[0009] A uniform magnetic field module, used for providing a uniform magnetic field with different magnetic field strengths to the sample to be tested according to a second control signal;

[0010] A test fixture module is connected to the microwave source module and is used for:

[0011] Placing the sample to be tested, wherein the sample to be tested is placed in the middle of the test fixture, and the test fixture is located in the middle of the uniform magnetic field, and the sample to be tested generates spin wave resonance under the environment of the uniform magnetic field and microwave excitation;

[0012] Under the action of the spin wave resonance, the amplitude of the microwave emitted by the test fixture changes;

[0013] detecting the amplitude of the changed microwave, converting the changed microwave signal into a first voltage signal through a diode power detector, and outputting the first voltage signal;

[0014] The Helmholtz coil module is connected to the output end of the lock-in amplifier module, and the lock-in amplifier module is used to provide an alternating voltage of a fixed frequency to the Helmholtz coil module; and the test fixture module is located in the middle of the Helmholtz coil module;

[0015] The lock-in amplifier module is connected to the test fixture module and the Helmholtz coil module respectively, and is used for:

[0016] Providing a reference signal for the lock-in amplifier module to collect the first voltage signal according to the fixed-frequency alternating voltage signal, thereby collecting the first voltage signal at the same frequency and filtering out complex background signals;

[0017] A data processing module is connected to the microwave source module, the uniform magnetic field module and the lock-in amplifier module respectively, and is used to:

[0018] sending the first control signal;

[0019] sending the second control signal;

[0020] Performing three-dimensional drawing processing on the microwave frequency, uniform magnetic field strength, and first voltage signal to obtain a dispersion relationship diagram;

[0021] According to the dispersion relationship diagram, in-plane spin wave standing waves of different orders are obtained, and data on the variation of the in-plane spin wave standing wave resonance frequency with the wave vector under different magnetic fields are obtained.

[0022] Optionally, the uniform magnetic field module includes:

[0023] The electromagnet unit is used to provide a static uniform magnetic field to the sample to be tested.

[0024] Optionally, the test fixture module comprises:

[0025] A coplanar waveguide plate, used for placing the sample to be tested;

[0026] A coaxial adapter, wherein both ends of the coplanar waveguide plate are respectively connected to the coaxial adapter; the coplanar waveguide plate is fixed at the center point of the Helmholtz coil; the central conductor strip in the coplanar waveguide plate is parallel to the magnetic field direction of the Helmholtz coil;

[0027] Coaxial cable; the coaxial adapter is connected to the microwave source module via the coaxial cable;

[0028] A diode power detector is connected to the coaxial adapter, and is used to detect the amplitude of the changed microwave, convert the changed microwave signal into a first voltage signal, and output the first voltage signal. The test fixture module is placed at the center point of the static uniform magnetic field.

[0029] Optionally, the coplanar waveguide plate comprises:

[0030] A central conductor strip for transmitting microwave signals;

[0031] A ground plane; the ground plane is located on both sides of the central conductor strip and is evenly distributed on the entire coplanar waveguide plate; there is a gap between the central conductor strip and the ground plane;

[0032] N electrostatic shielding holes, used to confine microwaves and shield interference from external electromagnetic waves;

[0033] The back side is covered with metal; the back side covering metal is connected to the ground plane on the front side.

[0034] Optionally, the data processing module includes:

[0035] A ferromagnetic resonance image drawing unit, used for drawing a ferromagnetic resonance image of the first voltage signal at different microwave frequencies as the intensity of the uniform magnetic field changes;

[0036] A three-dimensional drawing unit, connected to the ferromagnetic resonance image drawing module, for performing three-dimensional drawing processing on the ferromagnetic resonance image to obtain a dispersion relationship diagram of frequency versus magnetic field;

[0037] A spin wave resonance frequency point extraction unit is connected to the three-dimensional drawing unit and is used to extract in-plane standing waves of different orders in the dispersion relation diagram, and obtain spin wave resonance frequency points of different orders under the corresponding uniform magnetic field strength according to the intersection points of the in-plane standing waves and different uniform magnetic field strengths;

[0038] The spectrum drawing unit is connected to the spin wave resonance frequency point extraction unit and is used to draw spectrum diagrams of resonance frequencies with different orders of in-plane standing waves under different magnetic fields according to the spin wave resonance frequency points.

[0039] Optionally, different wave vectors corresponding to each order of standing waves are obtained according to different orders of the in-plane standing waves; thereby, a frequency spectrum of the resonance frequency points of the standing waves in the spin wave plane under different uniform magnetic field intensities along with the wave vectors is plotted; and the different wave vectors are used to characterize the test results of the spin wave dispersion spectrum based on the microwave method to achieve wave vector resolution.

[0040] To achieve the above purpose, the embodiment of the present invention also provides the following solution:

[0041] A method for testing spin wave dispersion spectrum based on microwave method to achieve wave vector resolution, comprising:

[0042] According to the first control signal, microwaves of different frequencies are emitted to the sample to be tested through the coplanar waveguide plate in the test fixture module; according to the second control signal, uniform magnetic fields of different magnetic field strengths are provided to the sample to be tested; and the data processing module sends the first control signal and the second control signal;

[0043] The sample to be tested generates spin wave resonance in a uniform magnetic field and microwave excitation environment; under the action of the spin wave resonance, the amplitude of the microwave changes, and the changed microwave is obtained;

[0044] Detecting the amplitude of the changed microwave; converting the amplitude of the changed microwave into a corresponding first voltage signal, and outputting the first voltage signal;

[0045] Performing three-dimensional drawing processing on the microwave frequency, uniform magnetic field strength, and first voltage signal to obtain a dispersion relationship diagram;

[0046] According to the dispersion relationship diagram, in-plane spin wave standing waves of different orders are obtained, and data on the variation of the in-plane spin wave standing wave resonance frequency with the wave vector under different magnetic fields are obtained.

[0047] The beneficial effects in the embodiments of the present invention include:

[0048] (1) The microwave source module emits microwaves of different frequencies to the sample to be tested, and uses microwave means to achieve the wave vector resolution function;

[0049] (ii) the data processing module performs three-dimensional drawing processing on the electromagnetic wave frequency, uniform magnetic field strength, first voltage signal and second voltage signal to obtain a dispersion relation diagram, thereby realizing the wave vector resolution function that can only be achieved by Brillouin in the prior art;

[0050] (3) The test efficiency is very high. In the prior art, the Brillouin test takes several hours to test a single curve, which requires huge human and material costs. However, the data processing module of the spin wave dispersion spectrum test system that realizes wave vector resolution based on the microwave method only takes three minutes to test a curve.

[0051] (iv) In the spin wave dispersion spectrum test results, considering only one ferromagnetic resonance curve, its test accuracy is as high as that of the commercial comprehensive physical property measurement system (PPMS);

[0052] (V) The microwave source module emits microwaves of different frequencies to the sample to be tested. The test frequency can be as high as 40 GHz (when a high-frequency microwave source is used), while the frequency of the high-frequency magnetic signal tested by the short-circuited microstrip line in the prior art can only reach 9 GHz;

[0053] (VI) The microwave-based spin wave dispersion spectrum test system that achieves wave vector resolution has no restrictions on the size of the sample to be tested;

[0054] (VII) The entire testing process of the spin wave dispersion spectrum testing system that realizes wave vector resolution based on the microwave method is convenient, fast and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0056] Figure 1 A schematic diagram of the structure of a spin wave dispersion spectrum testing system for realizing wave vector resolution based on a microwave method provided in an embodiment of the present invention;

[0057] Figure 2 A flow chart of a spin wave dispersion spectrum testing method for realizing wave vector resolution based on a microwave method provided in an embodiment of the present invention;

[0058] Figure 3 A schematic diagram of the structure of a coplanar waveguide plate provided in an embodiment of the present invention;

[0059] Figure 4 A detailed structural diagram of a spin wave dispersion spectrum testing system for realizing wave vector resolution based on a microwave method provided in an embodiment of the present invention;

[0060] Figure 5 A schematic diagram of the dispersion relationship between frequency and magnetic field provided in an embodiment of the present invention;

[0061] Figure 6 Schematic diagram of in-plane standing waves of different orders provided by an embodiment of the present invention;

[0062] Figure 7 A schematic diagram of the intersection of an in-plane standing wave and different magnetic fields provided in an embodiment of the present invention;

[0063] Figure 8 A schematic diagram of a spectrum diagram of the resonance frequency points of standing waves in a spin wave plane along with wave vectors under different uniform magnetic field intensities provided by an embodiment of the present invention.

[0064] Explanation of symbols:

[0065] Microwave source module-1, uniform magnetic field module-2, electromagnet unit-21, Helmholtz coil-4, test fixture module-3, coplanar waveguide plate-31, central conductor strip-311, ground plane-312, electrostatic shielding hole-313, back cover metal-314, spacing-315, coaxial adapter-32, diode power detector-33, lock-in amplifier module-5, data processing module-6, sample to be tested-10. DETAILED DESCRIPTION

[0066] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0067] The purpose of the present invention is to provide a spin wave dispersion spectrum testing method and system based on microwave method to achieve wave vector resolution, so as to solve the problems of low wave vector resolution efficiency and low accuracy of existing spin wave spectroscopy.

[0068] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0069] Figure 1 and Figure 4 An exemplary structure of the above-mentioned spin wave dispersion spectrum testing system that realizes wave vector resolution based on the microwave method is shown.

[0070] The microwave source module 1 is used to transmit microwaves of different frequencies to the sample to be tested through the coplanar waveguide plate of the test fixture according to the first control signal;

[0071] In one example, the sample to be tested may be Fe 20 Ni 80 The (FeNi) film has a thickness of 50nm, and micron strips of equal width and spacing are engraved on the film using micromachining technology. The width and spacing of the strips are both 3μm, and the length of the strips is 4mm. The microwave source module 1 is used to emit microwaves to realize the spin wave dispersion test with wave vector resolution function. This spin wave dispersion test with wave vector resolution can only be realized by Brillouin in the past.

[0072] The uniform magnetic field module 2 is used to provide a uniform magnetic field with different magnetic field strengths to the sample to be tested according to the second control signal;

[0073] The uniform magnetic field module 2 comprises:

[0074] The electromagnet unit 21 is used to provide a static uniform magnetic field to the sample to be tested.

[0075] The test fixture module 3 is connected to the microwave source module 1, and is used to place the sample to be tested. The test fixture is located in the middle of the uniform magnetic field. The sample to be tested generates spin wave resonance under the uniform magnetic field and microwave excitation environment.

[0076] Under the action of the spin wave resonance, the amplitude of the microwave emitted by the test fixture changes;

[0077] detecting the amplitude of the changed microwave, converting the changed microwave signal into a first voltage signal through a diode power detector, and outputting the first voltage signal;

[0078] The test fixture module 3 comprises:

[0079] The coplanar waveguide plate 31 is used to place the sample to be tested;

[0080] Both ends of the coplanar waveguide plate 31 are connected to the coaxial adapter 32 respectively; the coplanar waveguide plate 31 is fixed at the center point of the Helmholtz coil 4; the central conductor strip 311 in the coplanar waveguide plate 31 is parallel to the magnetic field direction of the Helmholtz coil 4;

[0081] The coaxial adapter 32 is connected to the microwave source module 1 via the coaxial cable;

[0082] The diode power detector 33 is connected to the coaxial adapter 32, and is used to detect the amplitude of the changed microwave, convert the changed microwave signal into a first voltage signal, and output the first voltage signal; the test fixture module 3 is placed at the center point of the static uniform magnetic field.

[0083] In one example, both ends of the coplanar waveguide plate 31 are connected to the coaxial adapter 32 by welding technology. The diode power detector 33 is connected to the signal input end of the phase-locked amplifier module 5 through a radio frequency adapter line. The coplanar waveguide plate 31 is fixed at the center of the Helmholtz coil 4, and the long axis direction of the coplanar waveguide plate 31 is parallel to the direction of the magnetic field of the Helmholtz coil 4. The coplanar waveguide plate 31 includes:

[0084] The central conductor strip 311 is used to transmit microwave signals;

[0085] The ground plane 312 is located on both sides of the central conductor strip and is evenly distributed on the entire coplanar waveguide plate; there is a spacing 315 between the central conductor strip 311 and the ground plane 312;

[0086] N electrostatic shielding holes 313 are used to confine microwaves and shield external electromagnetic interference;

[0087] The back side covering metal 314 and the front side ground plane 312 are connected via an electrostatic shielding hole 313 .

[0088] like Figure 3 As shown, the coplanar waveguide plate 31 is an impedance-matched coplanar waveguide plate. The dielectric plate of the coplanar waveguide plate 31 is a RO4003C microwave PCB produced by Rogers Company, with a length of 25 mm and a width of 18 mm. A metal 312Cu layer with a thickness of 15 μm is deposited on the PCB, and a layer of Au with a thickness of 0.025 μm is covered on the Cu layer as a protective layer. The coplanar waveguide plate includes a central conductor strip 311 for transmitting signals, which has a size of 1.14 mm in width, infinitely large ground planes 312 on both sides, and a spacing 315 between the central conductor strip 311 and the ground plane 312, and the spacing is 0.2413 mm. The electrostatic shielding holes 313 are evenly distributed on the coplanar waveguide plate, the diameter of the small holes is 0.508 mm, and the spacing between the holes is 1.02 mm. The back of the coplanar waveguide plate is completely covered with metal 314 and the ground plane 312 on the front is connected through the electrostatic shielding holes 313.

[0089] The diode power detector 33 is connected to the test fixture module 3, and the diode power detector 33 is used to:

[0090] detecting the amplitude of the changed microwave, converting the changed microwave signal into a first voltage signal, and outputting the first voltage signal;

[0091] The Helmholtz coil module 4 is connected to the output end of the phase-locked amplifier module 5, and the phase-locked amplifier module 5 is used to provide an alternating voltage of a fixed frequency to the Helmholtz coil module 4; and the test fixture module 3 is located in the middle of the Helmholtz coil module 4;

[0092] The lock-in amplifier module 5 is connected to the test fixture module 3 and the Helmholtz coil module 4 respectively, and is used for:

[0093] Providing a reference signal for the lock-in amplifier module to collect the first voltage signal according to the fixed-frequency alternating voltage signal, thereby collecting the first voltage signal at the same frequency and filtering out complex background signals;

[0094] The data processing module 6 is connected to the microwave source module 1, the uniform magnetic field module 2 and the lock-in amplifier module 5 respectively, and is used for:

[0095] sending the first control signal;

[0096] sending the second control signal;

[0097] Performing three-dimensional drawing processing on the microwave frequency, uniform magnetic field strength, and first voltage signal to obtain a dispersion relationship diagram;

[0098] According to the dispersion relationship diagram, in-plane spin wave standing waves of different orders are obtained, and data on the variation of the in-plane spin wave standing wave resonance frequency with the wave vector under different magnetic fields are obtained.

[0099] In one example, the Helmholtz coil 4 is connected to the signal output end of the phase-locked amplifier module 5 through a phase-locked dedicated test line. The phase-locked amplifier module 5 can provide a very small alternating voltage signal (voltage amplitude 2V, frequency 490Hz) to the Helmholtz coil 4. The sample to be tested 10 is placed on the coplanar waveguide plate 31, and the entire coplanar waveguide plate 31 is placed in the electromagnet unit 21. The collected signal is transmitted to the data processing module 6, and the size of the magnetic field of the uniform magnetic field module 2 and the size of the frequency of the microwave source module 1 are also controlled by the data processing module 6.

[0100] The data processing module 6 includes:

[0101] A ferromagnetic resonance image drawing unit, used for drawing a ferromagnetic resonance image of the first voltage signal at different microwave frequencies as the intensity of the uniform magnetic field changes;

[0102] A three-dimensional drawing unit, connected to the ferromagnetic resonance image drawing module, for performing three-dimensional drawing processing on the ferromagnetic resonance image to obtain a dispersion relationship diagram of frequency versus magnetic field;

[0103] A spin wave resonance frequency point extraction unit is connected to the three-dimensional drawing unit and is used to extract in-plane standing waves of different orders in the dispersion relation diagram, and obtain spin wave resonance frequency points of different orders under the corresponding uniform magnetic field strength according to the intersection points of the in-plane standing waves and different uniform magnetic field strengths;

[0104] The spectrum drawing unit is connected to the spin wave resonance frequency point extraction unit and is used to draw spectrum diagrams of resonance frequencies with different orders of in-plane standing waves under different magnetic fields according to the spin wave resonance frequency points.

[0105] According to the different orders of the in-plane standing wave, different wave vectors corresponding to each order of the standing wave are obtained; thereby, a frequency spectrum diagram of the resonance frequency points of the in-plane standing wave of the spin wave under the different uniform magnetic field intensities with the wave vector is drawn; the different wave vectors are used to characterize the spin wave dispersion spectrum test results based on the microwave method to achieve wave vector resolution.

[0106] In one example, the coplanar waveguide plate 31 provides a sufficiently large static uniform magnetic field through the electromagnet unit 21 (DC electromagnet) to completely magnetize the sample 10 to be tested, and the direction of the magnetic moment is arranged along the direction of the static uniform magnetic field. The microwave source module 1 provides a microwave excitation signal for the sample. The microwave source module 1 is connected to the coplanar waveguide plate 31 as a signal input terminal. The sample 10 to be tested is placed on the coplanar waveguide plate 31, and under microwave excitation, the magnetic moment in the sample 10 to be tested performs forced vibration around the direction of the static uniform magnetic field, which can also be called magnetic moment precession. The magnetic parameters of the sample to be tested can be analyzed by the trajectory of the magnetic moment precession. This magnetic moment precession will bring about changes in the microwave signal (amplitude). The microwave signal will be converted into a voltage signal through the diode power detector 33, and the voltage signal will be collected by the phase-locked amplifier module 5. Therefore, detecting its voltage signal can detect the precession state of the magnetic moment. Changing the size of the static uniform magnetic field will change the precession frequency of the magnetic moment in the sample to be tested. When this frequency is consistent with the frequency of the microwave (excitation signal), the microwave absorption becomes stronger, and a sharp change in the voltage signal can be seen. The Helmholtz coil 4 is connected to the output end of the phase-locked amplifier module 5, so that an alternating voltage with a fixed frequency can be provided to the Helmholtz coil 4. The alternating voltage signal with a fixed frequency provides a reference signal for the phase-locked amplifier module 5 to collect the first voltage signal, so that the first voltage signal at the same frequency is collected and the complex background signal is filtered out; the ferromagnetic resonance curve graph that changes with the magnetic field at different frequencies can be detected by changing the size of the magnetic field of the electromagnet unit 21.

[0107] The ferromagnetic resonance diagrams at all frequencies can be processed into three-dimensional graphs to obtain the dispersion relationship diagram of frequency and magnetic field, such as Figure 5 As shown, the horizontal axis H is the magnetic field intensity and the vertical axis f is the frequency. In the dispersion relationship diagram, we can find in-plane standing waves of different orders, such as Figure 6 As shown, through the intersection of the in-plane standing wave and different magnetic fields, such as Figure 7 As shown, the resonant frequency points of spin waves of different orders under the same magnetic field can be found, so that the spectrum of the resonant frequency with different orders of in-plane standing waves under different magnetic fields can be derived. The different orders of in-plane standing waves can be used to deduce the different wave vectors corresponding to each order of standing waves according to the formula (k=nπ / d, k represents the wave vector, n represents the order of in-plane standing waves, and d represents the width of the micron strip), as shown in Figure 8 As shown, the horizontal axis Wavevector represents the wave vector, and Intensity represents the relative intensity. That is, through the current device, we can easily and conveniently obtain the spin wave dispersion test with wave vector resolution function.

[0108] In summary, the microwave source module emits microwaves of different frequencies to the sample to be tested; the uniform magnetic field module provides a uniform magnetic field of different magnetic field strengths to the sample to be tested; the sample to be tested generates spin wave resonance in a uniform magnetic field and microwave excitation environment; the amplitude of the microwave changes under the action of the spin wave resonance, and the changed microwave is obtained; the diode power detector converts the changed microwave signal into a corresponding first voltage signal; the lock-in amplifier module collects the first voltage signal; the data processing module performs three-dimensional drawing processing on the microwave frequency, uniform magnetic field strength, and the first voltage signal to obtain a dispersion relationship diagram; and the spin wave dispersion spectrum test result is obtained. The present invention improves the wave vector resolution efficiency and accuracy of the spin wave dispersion spectrum.

[0109] To achieve the above purpose, the embodiment of the present invention also provides the following solution:

[0110] A microwave-based spin wave dispersion spectrum test method for wave vector resolution, see Figure 2 ,include:

[0111] Step 1: According to a first control signal, microwaves of different frequencies are emitted to the sample to be tested through the coplanar waveguide plate in the test fixture module; according to a second control signal, a uniform magnetic field of different magnetic field strengths is provided to the sample to be tested; a data processing module sends the first control signal and the second control signal;

[0112] Step 2: The sample to be tested generates spin wave resonance in a uniform magnetic field and microwave excitation environment; under the action of the spin wave resonance, the amplitude of the microwave changes, and the changed microwave is obtained;

[0113] Step 3: Detecting the amplitude of the changed microwave; converting the changed microwave amplitude into a corresponding first voltage signal, and outputting the first voltage signal;

[0114] Step 4: performing three-dimensional drawing processing on the microwave frequency, uniform magnetic field strength, and first voltage signal to obtain a dispersion relationship diagram;

[0115] Step 5: Obtain in-plane spin wave standing waves of different orders according to the dispersion relationship diagram, and obtain data on the variation of the in-plane spin wave standing wave resonance frequency with the wave vector under different magnetic fields.

[0116] Embodiment 1:

[0117] (1) Placing the sample 10 to be tested in the middle of the coplanar waveguide plate 31;

[0118] (2) Adjust the frequency of microwave source module 1 (9kHz-20 GHz);

[0119] (3) Setting the variation range and step size of the uniform magnetic field module 2;

[0120] (4) Testing the ferromagnetic resonance spectrum at different frequencies;

[0121] (5) The ferromagnetic resonance images of all frequencies are processed into three-dimensional images to obtain the dispersion relationship diagram of frequency versus magnetic field;

[0122] (6) In the dispersion relation diagram, different orders of in-plane standing waves can be found. Through the intersection of the in-plane standing waves and different magnetic fields, the resonant frequency points of spin waves of different orders under the same magnetic field can be found.

[0123] (7) Thus, the spectrum of the resonance frequency with different orders of in-plane standing waves under different magnetic fields can be derived. The different orders of in-plane standing waves can be used to deduce the different wave vectors corresponding to each order of standing waves, thereby realizing the spin wave dispersion spectrum test with wave vector resolution.

[0124] In order to reduce experimental errors, the entire method was implemented on a vibration-damping table to reduce the impact of environmental vibration on microwave transmission.

[0125] Furthermore, the present invention also provides an electronic device, which may include: a processor, a communication interface, a memory and a communication bus. The processor, the communication interface and the memory communicate with each other through the communication bus. The processor may call a computer program in the memory to execute the spin wave dispersion spectrum testing method based on the microwave method to achieve wave vector resolution when the processor executes the computer program.

[0126] In addition, when the computer program in the above-mentioned memory is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk or an optical disk.

[0127] Furthermore, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed, the spin wave dispersion spectrum testing method based on the microwave method to achieve wave vector resolution is implemented.

[0128] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0129] This article uses specific examples to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only used to help understand the methods and core ideas of the embodiments of the present invention. At the same time, for those skilled in the art, according to the ideas of the embodiments of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the embodiments of the present invention.

Claims

1. A spin wave dispersion spectrum testing system based on microwave method to achieve wave vector resolution, characterized in that: include: A microwave source module is used to transmit microwaves of different frequencies to the sample to be tested through the coplanar waveguide plate of the test fixture according to the first control signal; the sample to be tested is specifically a strip film with a film thickness of 50nm, and micron strips of equal width and spacing are engraved on the film using micromachining technology, the width and spacing of the micron strips are both 3μm, and the length of the micron strips is 4mm; A uniform magnetic field module, used for providing a uniform magnetic field with different magnetic field strengths to the sample to be tested according to a second control signal; A test fixture module is connected to the microwave source module and is used for: Placing the sample to be tested, wherein the sample to be tested is placed in the middle of the test fixture, and the test fixture is located in the middle of the uniform magnetic field, and the sample to be tested generates spin wave resonance under the environment of the uniform magnetic field and microwave excitation; Under the action of the spin wave resonance, the amplitude of the microwave emitted by the test fixture changes; detecting the amplitude of the changed microwave, converting the changed microwave signal into a first voltage signal through a diode power detector, and outputting the first voltage signal; The Helmholtz coil module is connected to the output end of the lock-in amplifier module, and the lock-in amplifier module is used to provide an alternating voltage of a fixed frequency to the Helmholtz coil module; and the test fixture module is located in the middle of the Helmholtz coil module; The lock-in amplifier module is connected to the test fixture module and the Helmholtz coil module respectively, and is used for: Providing a reference signal for the lock-in amplifier module to collect the first voltage signal according to the fixed-frequency alternating voltage signal, thereby collecting the first voltage signal at the same frequency and filtering out complex background signals; A data processing module is connected to the microwave source module, the uniform magnetic field module and the lock-in amplifier module respectively, and is used to: sending the first control signal; sending the second control signal; Performing three-dimensional drawing processing on the microwave frequency, uniform magnetic field strength, and first voltage signal to obtain a dispersion relationship diagram; According to the dispersion relation diagram, different orders of in-plane spin wave standing waves are obtained, and data on the variation of the in-plane spin wave standing wave resonance frequency with the wave vector under different magnetic fields are obtained; The data processing module comprises: A ferromagnetic resonance image drawing unit, used for drawing a ferromagnetic resonance image of the first voltage signal at different microwave frequencies as the intensity of the uniform magnetic field changes; A three-dimensional drawing unit, connected to the ferromagnetic resonance image drawing module, for performing three-dimensional drawing processing on the ferromagnetic resonance image to obtain a dispersion relationship diagram of frequency versus magnetic field; A spin wave resonance frequency point extraction unit is connected to the three-dimensional drawing unit and is used to extract in-plane standing waves of different orders in the dispersion relation diagram, and obtain spin wave resonance frequency points of different orders under the corresponding uniform magnetic field strength according to the intersection points of the in-plane standing waves and different uniform magnetic field strengths; A spectrum plotting unit, connected to the spin wave resonance frequency point extraction unit, for plotting spectrum plots of resonance frequencies with different orders of in-plane standing waves under different magnetic fields according to the spin wave resonance frequency points; According to the different orders of the in-plane standing wave, different wave vectors corresponding to each order of the standing wave are obtained; thereby drawing a spectrum diagram of the resonance frequency point of the in-plane standing wave of the spin wave under the different uniform magnetic field strengths with the wave vector; the different wave vectors are used to characterize the test results of the spin wave dispersion spectrum based on the microwave method to achieve wave vector resolution; In-plane standing waves of different orders are found in the dispersion relationship diagram, and the resonance frequency points of spin waves of different orders under the same magnetic field are found through the intersection of the in-plane standing waves and different magnetic fields. The spectrum diagram of the resonance frequency with different orders of in-plane standing waves under different magnetic fields is derived. The different orders of in-plane standing waves are used to deduce the different wave vectors corresponding to each order of standing waves according to the formula k=nπ / d, and a spin wave dispersion test with wave vector resolution function is obtained; where k is the wave vector, n is the order of the in-plane standing wave, and d is the width of the micron strip.

2. The spin wave dispersion spectrum testing system for wave vector resolution based on microwave method according to claim 1, characterized in that: The uniform magnetic field module comprises: The electromagnet unit is used to provide a static uniform magnetic field to the sample to be tested.

3. The spin wave dispersion spectrum testing system for wave vector resolution based on microwave method according to claim 2, characterized in that: The test fixture module comprises: A coplanar waveguide plate, used for placing the sample to be tested; A coaxial adapter, wherein both ends of the coplanar waveguide plate are respectively connected to the coaxial adapter; the coplanar waveguide plate is fixed at the center point of the Helmholtz coil; the central conductor strip in the coplanar waveguide plate is parallel to the magnetic field direction of the Helmholtz coil; Coaxial cable; the coaxial adapter is connected to the microwave source module via the coaxial cable; A diode power detector is connected to the coaxial adapter, and is used to detect the amplitude of the changed microwave, convert the changed microwave signal into a first voltage signal, and output the first voltage signal; the test fixture module is placed at the center point of the static uniform magnetic field.

4. The spin wave dispersion spectrum testing system for wave vector resolution based on microwave method according to claim 3, characterized in that: The coplanar waveguide plate comprises: A central conductor strip for transmitting microwave signals; A ground plane; the ground plane is located on both sides of the central conductor strip and is evenly distributed on the entire coplanar waveguide plate; there is a gap between the central conductor strip and the ground plane; N electrostatic shielding holes, used to confine microwaves and shield interference from external electromagnetic waves; The back side is covered with metal; the back side covering metal is connected to the ground plane on the front side.

5. A method for testing spin wave dispersion spectrum based on microwave method to achieve wave vector resolution, characterized in that: include: emitting microwaves of different frequencies to the sample to be tested through the coplanar waveguide plate in the test fixture module according to the first control signal; According to the second control signal, a uniform magnetic field with different magnetic field strengths is provided to the sample to be tested; the data processing module sends the first control signal and the second control signal; the sample to be tested is specifically a strip film with a film thickness of 50nm, and micron strips with equal width and spacing are engraved on the film using micromachining technology, the width and spacing of the micron strips are both 3μm, and the length of the micron strips is 4mm; The sample to be tested generates spin wave resonance in a uniform magnetic field and microwave excitation environment; under the action of the spin wave resonance, the amplitude of the microwave changes, and the changed microwave is obtained; Detecting the amplitude of the changed microwave; converting the amplitude of the changed microwave into a corresponding first voltage signal, and outputting the first voltage signal; Performing three-dimensional drawing processing on the microwave frequency, uniform magnetic field strength, and first voltage signal to obtain a dispersion relationship diagram; According to the dispersion relation diagram, different orders of in-plane spin wave standing waves are obtained, and data on the variation of the in-plane spin wave standing wave resonance frequency with the wave vector under different magnetic fields are obtained; The data processing module comprises: A ferromagnetic resonance image drawing unit, used for drawing a ferromagnetic resonance image of the first voltage signal at different microwave frequencies as the intensity of the uniform magnetic field changes; A three-dimensional drawing unit, connected to the ferromagnetic resonance image drawing module, for performing three-dimensional drawing processing on the ferromagnetic resonance image to obtain a dispersion relationship diagram of frequency versus magnetic field; A spin wave resonance frequency point extraction unit is connected to the three-dimensional drawing unit and is used to extract in-plane standing waves of different orders in the dispersion relation diagram, and obtain spin wave resonance frequency points of different orders under the corresponding uniform magnetic field strength according to the intersection points of the in-plane standing waves and different uniform magnetic field strengths; A spectrum plotting unit, connected to the spin wave resonance frequency point extraction unit, for plotting spectrum plots of resonance frequencies with different orders of in-plane standing waves under different magnetic fields according to the spin wave resonance frequency points; According to the different orders of the in-plane standing wave, different wave vectors corresponding to each order of the standing wave are obtained; thereby drawing a spectrum diagram of the resonance frequency point of the in-plane standing wave of the spin wave under the different uniform magnetic field strengths with the wave vector; the different wave vectors are used to characterize the test results of the spin wave dispersion spectrum based on the microwave method to achieve wave vector resolution; In-plane standing waves of different orders are found in the dispersion relationship diagram, and the resonance frequency points of spin waves of different orders under the same magnetic field are found through the intersection of the in-plane standing waves and different magnetic fields. The spectrum diagram of the resonance frequency with different orders of in-plane standing waves under different magnetic fields is derived. The different orders of in-plane standing waves are used to deduce the different wave vectors corresponding to each order of standing waves according to the formula k=nπ / d, and a spin wave dispersion test with wave vector resolution function is obtained; where k is the wave vector, n is the order of the in-plane standing wave, and d is the width of the micron strip.

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