Versatile magneto-optic Kerr effect polarimeter for studies of domain-wall dynamics in magnetic nanostructures

Abstract

This article describes a versatile instrument capable of probing magnetic domain-wall dynamics in microstructured thin films. The instrument combines a state-of-the-art scanning magneto-optic Kerr effect polarimeter that incorporates high-bandwidth signal detection, an integrated broadband magnet system, and a microwave probe station. Together, these subsystems enable a broad range of studies of field and current-driven domain-wall dynamics in submicrometer magnetic structures and devices. Domain-wall motion can be probed with ≈2μm spatial resolution and less than 2ns temporal resolution. That motion can be driven by magnetic fields of up to ≈100Oe amplitude with sinusoidal (>20MHz) or user-defined wave forms (20ns rise time) or by electric currents from dc to ≈10GHz. A detailed description of the instrument is provided as well as several experiments highlighting its capabilities, including hysteresis loop shape and magnetic energy loss measurements spanning ten decades of drive frequency; spatially and temporally resolved measurements of domain-wall propagation in submicrometer magnetic wires; and mobility measurements of field- and current-driven domain-wall motion.