Imaging and detection of periodic, 5–100 Hz magnetic fields with epitaxial rare earth-iron garnet films

Abstract

Sinusoidal magnetic fields with strengths as small as ~0.5 nT (RMS) and frequencies of 5 -100 Hz have been detected at room temperature by modulating the magneto-optical Kerr response of epitaxial rare earth-iron garnet films. Ferromagnetic nanoparticles with a mean size of 500 nm have also been detected in real time in a liquid flow stream at field strengths as low as 1 muT.