14GHz longitudinally detected electron spin resonance using microHall sensors.

In this work we developed a home-made LOngitudinally Detected Electron Spin Resonance (LODESR) spectrometer based on a microsize Hall sensor. A coplanar waveguide (CPW)-resonator is used to induce microwave-excitation on the sample at 14GHz. We used InSb cross-shaped Hall devices with active areas of (10μm×10μm) and (5μm×5μm). Signal intensities of the longitudinal magnetization component of DPPH and YIG samples of volumes about (10μm)3 and (5μm)3, are measured under amplitude and frequency modulated microwave magnetic field generated by the CPW-resonator. At room temperature, 109spins/G√Hz sensitivity is achieved for 0.2mT linewidth, a result which is still better than most of inductive detected LODESR sensitivities.