Method, system and apparatus for measuring comparatively thick materials

Patent metadata

Field	Value
Publication number	US-9766190-B2
Application number	US-201414496966-A
Country	US
Kind code	B2
Filing date	Sep 25, 2014
Priority date	Sep 25, 2013
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A method, system and apparatus are provided to measure magnetic characteristics of a comparatively thick magnetic sample in a magnetic field or nonmagnetic field by X-ray magnetic circular dichroism (XMCD). In particular, the method, system and apparatus measure the magnetic characteristics of the thick magnetic sample by irradiating the sample with X-ray, and detecting transmissive X-ray passing through the sample.

First claim

The invention claimed is:

1. A magnetic measurement method comprising:
measuring a magnetic characteristic of a single crystal particle of a magnetic sample of 50 nm˜1000 nm in thickness by:
irradiating the magnetic sample with X-ray that passes through at least one of a Fresnel zone plate (FZP) and an order-sorting aperture (OSA) that focuses X-ray flux passing through,
detecting an intensity of transmissive X-ray passing through the single crystal particle, and
determining, based on the detected intensity of transmissive X-ray passing through the single crystal particle, the magnetic characteristic of the single crystal particle.

2. The magnetic measurement method according to claim 1 , wherein the X-ray is a circular polarization X-ray.

3. The magnetic measurement method according to claim 2 , the method further comprising:
alternately irradiating the single crystal particle with a right-circular polarization X-ray and a left-circular polarization X-ray,
measuring X-ray absorption of each of the right-circular and left-circular polarization X-rays, respectively, and
detecting X-ray magnetic circular dichroism (XMCD), which is a difference between two X-ray absorptions, of the single crystal particle based on the X-ray absorption measurement results.

4. The magnetic measurement method according to claim 2 , further comprising:
measuring X-ray absorption in the magnetic sample's magnetic field parallel to a direction of polarization light and X-ray absorption in the magnetic sample's magnetic field anti-parallel to the direction of polarization light, respectively, and
detecting a difference between the two X-ray absorptions.

5. The magnetic measurement method according to claim 1 , further comprising, prior to the measurement, fabricating the magnetic sample into a microtome section of 50 nm˜1000 nm in thickness using focused ion beam etching.

6. The magnetic measurement method according to claim 1 , wherein the measurement is carried out within an external magnetic field.

7. The magnetic measurement method according to claim 1 , further comprising using an Avalanche photodiode (APD) to detect the intensity of transmission X-ray passing through the single crystal particle.

8. The magnetic measurement method according to claim 1 , wherein the X-ray applied to the sample is circular polarization X-ray focused into 10 nm in beam size.

9. The magnetic measurement method according to claim 1 , further comprising:
generating right-circular polarization X-ray and left-circular polarization X-ray which enters a measurement place of the sample,
successively detecting the transmission X-ray,
alternately measuring the intensity of the transmission X-ray corresponding to right-circular polarization X-ray and the intensity of the transmission X-ray corresponding to left-circular polarization X-ray,
detecting the difference between the two intensities, and
determining the magnetization inside of the magnetic sample based on the detected difference between the two intensities.

10. A magnetic measurement system comprising:
an X-ray source;
a monochromator that converts right- and left-polarization X-ray of the X-ray source into right- and left-monochromatic X-ray;
an aperture slit that allows the right- and left- monochromatic X-ray converted by the monochromator to pass through; and
a processor configured to:
measure a magnetic characteristic of a single crystal particle of a magetic sample of 50 nm˜1000 nm in thickness by:
causing the magnetic sample to he irradiated with X-ray that passes through at least one of a Fresnel zone plate (FZP) and an order-sorting aperture (OSA) that focuses X-ray flux passing through,
detecting an intensity of transmission X-ray passing through the single crystal particle, and
determining, based on the detected intensity of the transmissive X-ray passing through the single crystal particle, the magnetic characteristic of the single crystal particle.

11. The magnetic measurement system according to claim 10 , further comprising: an analytical section having a combination of a Fresnel zone plate (FZP) that receives and focuses the right- and left-monochromatic X-ray on a single point wide of a magnetic sample, an order-sorting aperture (OSA) that allows the X-ray focused by the FZP to selectively pass through, and a sample-stage configured to set a comparatively thick magnetic sample that is more than 150 nm thick and less than or equal to 1000 nm thick to be irradiated with the X-ray.

12. A magnetic measurement apparatus comprising:
an analytical section having a combination of a Fresnel zone plate (FZP) that focuses X-ray received from a monochromator on a single point of a polycrystalline magnetic sample, and an order-sorting aperture (OSA) that allows the X-ray focused by the FZP to selectively pass through, a sample-stage that is configured to set the polycrystalline magnetic sample that is more than 150 nm thick and less than or equal to 1000 nm thick to be irradiated with the X-ray passing through the OSA; and
a processor configured to:
measure a magnetic characteristic of a single crystal particle of the magnetic sample of 50 nm˜1000 nm in thickness by:
causing the magnetic sample to be irradiated with X-ray that passes through at least one of the FZP and the OSA,
detecting an intensity of transmission X-ray passing through the single crystal particle, and
determining, based on the detected intensity of the transmissive X-ray passing through the single crystal particle, the magnetic characteristic of the single crystal particle.

13. The magnetic measurement system according to claim 10 , wherein the processor is configured to: generate two-dimensional X-ray magnetic circular dichroism (XMCD) data, based on the detected transmittance of the transmission X-ray, of each single crystalline-grain contained in the sample by directly measuring transmittance of transmission X-ray passing through the single crystalline-grains even within an external magnet field.

14. The magnetic measurement system according to claim 10 , further comprising an Avalanche photodiode (APD) having dynamic ranges and optical fibers which are used within an external magnetic field, wherein the processor is configured to: use the APD to detect the intensity of transmission X-ray passing through the single crystal particle.

15. The magnetic measurement system according to claim 12 , further comprising: piezoelectric devices that control X-, Y- and Z-stages, of the analytical section, which includes the sample-stage of the analytical section with accuracy in nanometers.

16. The magnetic measurement apparatus according to claim 12 , further comprising: piezoelectric devices that control X-, Y- and Z-stages, of the analytical section, which includes the sample-stage of the analytical section with accuracy in nanometers.

17. The magnetic measurement apparatus according to claim 12 , wherein the processor is configured to: generate two-dimensional X-ray magnetic circular dichroism (XMCD) data, based on the detected transmittance of the transmission X-ray, of each single crystalline-grain contained in the sample by directly measuring transmittance of transmission X-ray passing through the single crystalline-grains even within an external magnet field.

18. The magnetic measurement apparatus according to claim 12 , further comprising an Avalanche photodiode (APD) having dynamic ranges and optical fibers which are used within an external magnetic field, wherein the processor is configured to: use the APD to detect the intensity of transmi

Assignees

• Toyota Motor Co Ltd
• Inter-University Res Inst Corp High Energy Accelerator Res Organization

Inventors

• Yano Masao
• Ono Kanta

Classifications

• G01N23/04 Primary

  and forming images of the material · CPC title

• G01N23/063 Primary

  Physics · mapped topic

• G01N27/72

  by investigating magnetic variables · CPC title

• G01N2223/405

  mapping of a material property · CPC title

• G01N23/085 Primary

  X-ray absorption fine structure [XAFS], e.g. extended XAFS [EXAFS] · CPC title