Magneto-optical study of the magnetization reversal process of Fe nanowires

Abstract

We discuss results of magneto-optical Kerr effect (MOKE) measurementsperformed on a thin Fe film of 13 nm thickness, which has been patterned into aperiodic arrangement of nanowires by means of optical interference lithography.The resulting array of nanowires consist of stripes having a width of 150 nm anda periodicity of 300 nm. MOKE hysteresis loops are measured withinmagnetic fields which are aligned in different directions, both parallel andperpendicular with respect to the direction of the nanowires as well as forvarious angles in between. A particular arrangement of the longitudinalKerr effect measurement allows us to identify both the longitudinal andthe transverse component of the magnetization of Fe nanowires. Fromthis both the angle and the magnitude of the magnetization vector M⃗ arederived. For a non-parallel alignment of the nanowires with respect to the direction of theexternal magnetic field, the hysteresis loops consist of a plateau region with two coercivefields Hc1and Hc2,which is discussed as resulting from an anisotropic pinning behaviour ofmagnetic domains in directions along and perpendicular to the nanowires.