In-Situ Torque Magnetometry: Magnetic Coupling in Fe/Cr/Fe Thin-Film Systems

Abstract

We have developed an ultra-sensitive torque magnetometer tailored to the study of thin-film interface magnetism and interlayer magnetic exchange coupling. The magnetometer was composed of an optical-fiber interferometer and a customized silicon cantilever that was fabricated using silicon micro-electromechanical system (MEMS) technology. The performance of the magnetometer was gauged by measuring the couplings of the Fe/Cr/Fe trilayer system deposited on a Si < 110 > substrate. The antiferomagnetic stacking of the Cr layers of the Fe/Cr/Fe system and the parallel or the antiparallel coupling between the bottom Fe and the top Fe layers with various Cr spacer thicknesses were monitored by using a MEMS torque magnetometer. We found short- (similar to 2.05 ML Cr spacer thickness) and long-period (similar to 13.80 ML Cr spacer thickness) oscillations of the interlayer exchange coupling of the Fe/Cr/Fe trilayer system.