14GHz longitudinally detected electron spin resonance using microHall sensors

Area of Science:

• Physics
• Materials Science
• Spectroscopy

Background:

• Electron Spin Resonance (ESR) is a powerful technique for studying materials with unpaired electrons.
• Traditional ESR detection methods can be limited in sensitivity and require specific sample conditions.
• Longitudinally Detected Electron Spin Resonance (LODESR) offers an alternative detection scheme.

Purpose of the Study:

• To develop a novel, home-made LODESR spectrometer utilizing a microsize Hall sensor.
• To investigate the performance and sensitivity of the developed LODESR spectrometer.
• To demonstrate the capability of the system for characterizing magnetic materials.

Main Methods:

• Construction of a custom LODESR spectrometer incorporating a microsize Hall sensor.
• Utilizing a coplanar waveguide (CPW)-resonator for microwave excitation at 14GHz.
• Employing Indium Antimonide (InSb) cross-shaped Hall devices with active areas of 10μm×10μm and 5μm×5μm.
• Measuring the longitudinal magnetization component of DPPH and YIG samples under modulated microwave magnetic fields.

Main Results:

• The developed LODESR spectrometer successfully measured signal intensities from DPPH and YIG samples.
• A sensitivity of 10^9 spins/√Hz was achieved at room temperature for a 0.2mT linewidth.
• This sensitivity surpasses that of most previously reported inductive-detected LODESR systems.

Conclusions:

• A functional home-made LODESR spectrometer based on a microsize Hall sensor has been successfully developed.
• The system demonstrates high sensitivity and potential for various applications in materials science and condensed matter physics.
• This work contributes to the advancement of ESR detection techniques, offering a more accessible and sensitive alternative.