CN-114858831-B - X-ray magnetic circle two-chromatograph measuring system and measuring method

Abstract

The invention discloses an X-ray magnetic circle dichroism spectrum measuring system and a measuring method, wherein the X-ray magnetic circle dichroism spectrum measuring system comprises: the device comprises a signal generation module, a power amplification module, an electromagnet module, a signal acquisition module and a phase-locked amplification module. The alternating magnetic field modulation XMC signals are combined with the phase-locked amplification technology, so that the weak XMC signals are effectively prevented from being annihilated in the background of a higher absorption spectrum, high-precision measurement of the weak XMC signals can be realized, and the measuring system and the measuring method have the advantages of simple structure, low construction cost and low debugging difficulty.

Inventors

• WANG CHAO
• ZHANG WENHUA
• YAN WENSHENG

Assignees

• 中国科学技术大学

Dates

Publication Date

20260512

Application Date

20220607

Claims (7)

1. 1. An X-ray magnetic circle dichromatic measurement system, comprising: The signal generation module receives the control instruction and sends out a low-power signal, wherein the low-power signal is divided into two paths, one path is used as a reference signal, and the other path is used as a modulation signal; the power amplification module receives the modulation signal and amplifies the modulation signal into high-power alternating exciting current with the same frequency; The electromagnet module generates an alternating magnetic field with the frequency being more than or equal to 1kHz under the action of high-power alternating exciting current and acts on a sample to be detected; The signal acquisition module is used for acquiring an X-ray absorption spectrum signal of the sample to be detected; and the phase-locked amplifying module is used for respectively receiving the reference signal and the X-ray absorption spectrum signal and separating an alternating current XMC signal from the back signal.
2. 2. The X-ray magneto-circular dichroism measurement system of claim 1, wherein the parameters of the low power signal comprise a waveform and a frequency, wherein the waveform is one of a square wave, a sine wave, a triangle wave, and a pulse wave.
3. 3. The X-ray magnetic circle dichroism measurement system of claim 1, wherein the signal acquisition module is a current detection module, a fluorescence detection module, or a luminescence detection module.
4. 4. The X-ray magneto-circular dichroism measurement system as in any one of claims 1-3 further comprising a control and read module that issues control instructions to control the signal generation module and read XMCD signals from the lock-in amplification module.
5. 5. An X-ray magneto-circular dichroism measurement method based on the X-ray magneto-circular dichroism measurement system according to any of claims 1-4, characterized in that the measurement method comprises the steps of: acquiring a low-power signal, dividing the low-power signal into two paths, wherein one path is used as a reference signal, and the other path is used as a modulation signal; amplifying the modulation signal into high-power alternating exciting current with the same frequency, and generating an alternating magnetic field to act on a sample to be detected based on the alternating exciting current; synchrotron radiation X-rays to a sample to be detected and collecting X-ray absorption spectrum signals of the sample to be detected; Performing phase-locked amplification operation based on the reference signal and the X-ray absorption spectrum signal, and separating an alternating XMC signal from the back signal; the XMCD signal is read.
6. 6. The method of claim 5, wherein the parameters of the low power signal include a waveform and a frequency, and wherein the waveform is one of a square wave, a sine wave, a triangle wave, and a pulse wave.
7. 7. The method of claim 5, wherein the collection of the X-ray absorption spectrum signal is performed by collecting a current, fluorescence or luminescence signal of the sample to be measured.

Description

X-ray magnetic circle two-chromatograph measuring system and measuring method Technical Field The invention belongs to the technical field of synchrotron radiation soft X-ray magnetic circle dichroism measurement, and particularly relates to an X-ray magnetic circle dichroism measurement system and an X-ray magnetic circle dichroism measurement method. Background The synchronous radiation soft X-ray spectroscopy technology mainly comprises an X-ray absorption spectrum (XAS), a Synchronous Radiation Photoelectron Emission Spectrum (SRPES), an X-ray emission spectrum (XES) and the like, is a powerful means for researching the atomic/electronic structure and chemical properties of functional materials, and has wide application in the research of atomic/electronic structures of a plurality of functional materials (such as two-dimensional ferromagnetic materials, spintronics materials, oxide heterojunction, lithium ion battery electrode materials and the like). Synchrotron radiation soft X-ray magnetic circular dichroism (XMCD) spectroscopy is an important magnetic characterization technique, and XMCD methods have elemental resolution and can distinguish the contributions of spin and orbital magnetic moments of a single element to macroscopic magnetic moments. Has irreplaceable roles in magnetic materials and spintronics research. In the measurement of synchrotron radiation XMCD spectroscopy, an XMCD signal is obtained by subtracting X-ray absorption spectra under two different test conditions, and currently, two main physically equivalent XMCD measurement methods are that (1) a sample is magnetized by using a magnetic field with a fixed direction, then the absorption spectra are measured by using soft X-rays with left-handed and right-handed circular polarization directions respectively, the difference spectrum of the two absorption spectra is the absorption spectrum contribution related to magnetic moment, namely an XMCD signal, and (2) the sample is magnetized by using a magnetic field with opposite directions twice, the absorption spectrum is measured by using soft X-rays with the fixed circular polarization direction after each magnetization, and the difference spectrum of the two absorption spectra is the XMCD signal. However, the amplitude of the XMCD signal of many important magnetic material systems is too low (less than 1%) in the total X-ray absorption spectrum signal, and extracting the XMCD signal has the problem of too low "signal-to-back ratio", especially for a thin film/interface system with a low proportion of the element to be measured, the weak XMCD signal is often annihilated in a high absorption spectrum signal background, and it is difficult to perform accurate measurement. The method utilizes two undulators to generate soft X rays with left-hand and right-hand circular polarization directions to be incident on a sample, and utilizes the phase-locked amplification method to extract XMC signals, but the experimental method needs to operate a specially designed double undulator beam line, and the double undulator beam line is rarely adopted in the synchronous radiation device worldwide due to complex structure, high construction cost and high debugging difficulty. In addition, the circularly polarized direction modulation frequency of the dual oscillator beam line is limited by the operating frequency of the kick rail magnet, which is typically no higher than 100Hz. Disclosure of Invention In view of the foregoing, it is necessary to provide an X-ray magnetic circle two-chromatograph measuring system that modulates a sample XMCD signal with an alternating magnetic field and performs lock-in amplification measurement, and that can implement high-precision measurement of a weak XMCD signal by combining lock-in amplification with a data acquisition system without upgrading a light source and a beam line system. In order to achieve the above purpose, the present invention adopts the following technical scheme: The invention first provides an X-ray magnetic circle dichroism measuring system, which comprises: The signal generation module receives the control instruction and sends out a low-power signal, wherein the low-power signal is divided into two paths, one path is used as a reference signal, and the other path is used as a modulation signal; the power amplification module receives the modulation signal and amplifies the modulation signal into high-power alternating exciting current with the same frequency; The electromagnet module generates an alternating magnetic field under the action of high-power alternating exciting current and acts on a sample to be tested; The signal acquisition module is used for acquiring an X-ray absorption spectrum signal of the sample to be detected; and the phase-locked amplifying module is used for respectively receiving the reference signal and the X-ray absorption spectrum signal and separating an alternating current XMC signal from the back signal. Further,