Hard-X-ray magnetic microscopy and local magnetization analysis using synchrotron radiation.

Area of Science:

• Materials Science
• Physics
• Chemistry

Background:

• X-ray microscopy provides unique capabilities compared to electron microscopy, including internal sample observation and analysis under various conditions (e.g., wet, high pressure, magnetic fields).
• Advancements in X-ray focusing optics have enabled X-ray nanoscopy, achieving beam sizes down to 7 nm.
• X-ray spectroscopy offers element selectivity and sensitivity to chemical states and magnetic properties.

Purpose of the Study:

• To present recent studies on magnetic microscopy and local magnetic analysis using hard X-rays.
• To describe instrumentation developments enabling nanoscale X-ray analysis.
• To showcase applications of X-ray nanospectroscopy and magnetic circular dichroism (XMCD) spectroscopy.

Main Methods:

• Utilizing a hard X-ray nanospectroscopy station (BL39XU at SPring-8) with focusing optics producing a 100 × 100 nm beam.
• Performing X-ray absorption fine structure (XAFS) spectroscopy with nanoscale resolution (nano-XAFS).
• Conducting magnetic circular dichroism (XMCD) spectroscopy with sub-micrometer resolution, including scanning XMCD imaging and element-specific magnetometry.

Main Results:

• Nano-XAFS successfully visualized chemical states in particle catalysts and phase-change memory devices.
• Magnetization reversal processes in individual magnetic CoPt dots were directly observed using XMCD.
• Chemical distribution and magnetic domain evolution in Nd-Fe-B magnets during demagnetization were imaged.

Conclusions:

• Hard X-ray microscopy and nanospectroscopy are powerful tools for local chemical and magnetic analysis at the nanoscale.
• Advancements in instrumentation, particularly focusing optics, are driving progress in X-ray microscopy.
• These techniques complement electron microscopy and offer unique insights into material properties and behavior.