Field-angle-dependent multi-frequency electron spin resonance spectroscopy in submillimeter wave range based on...

Area of Science:

• Physics
• Condensed Matter Physics
• Spectroscopy

Background:

• Electron spin resonance (ESR) is a powerful technique for probing magnetic properties.
• High-frequency ESR (millimeter and submillimeter waves) offers unique insights but requires sensitive detection methods.
• Existing methods often face limitations in sensitivity or experimental flexibility.

Purpose of the Study:

• To develop a novel, highly sensitive thermally detected ESR spectrometer.
• To enable precise field-angle-dependent ESR measurements at high frequencies (above 500 GHz).
• To demonstrate the technique's utility in studying complex magnetic materials.

Main Methods:

• Utilized a cantilever-shaped device for detecting ESR absorption via temperature differences.
• Operated the system under high vacuum conditions at low temperatures (10 K).
• Integrated the device into a 10 T split-pair superconducting magnet with a 25 mm bore.

Main Results:

• Achieved a spin sensitivity of approximately 10^12 spins/G at 10 K.
• Demonstrated the capability for precise, multi-frequency, field-angle-dependent ESR measurements.
• Successfully studied the excitation energy of the dimer triplet state in SrCu2(BO3)2.

Conclusions:

• The developed thermally detected ESR spectrometer offers exceptional sensitivity and experimental versatility.
• This technique is suitable for investigating the magnetic properties of quantum materials in high magnetic fields.
• The study provides valuable insights into the Shastry-Sutherland magnet SrCu2(BO3)2.