A microcoil for magnetization reset during time-resolved magneto-optical measurements (article)

Abstract

Stroboscopic pump-probe measurements are a well established means of studying magnetic phenomena on sub-picosecond timescales, but are typically reliant on a constant external magnetic field to reset the magnetic state after application of each pump pulse. Here, a microcoil is presented that can generate a pulsed reset field with duration of 2.1 µs and amplitude greater than 160 mT, at kHz repetition rates. Operation of the device is demonstrated through magnetic switching measurements recorded with a continuous wave laser and a detector connected to an oscilloscope. Studies of ferromagnetic multilayer thin films and a ferrimagnetic insulating garnet film, each with perpendicular magnetic anisotropy, reveal distinctly different switching behavior that is understood in terms of the different domain configurations and dynamics within the materials. Such measurements are essential to ensure effective reset before pump-probe measurements may be attempted, and inform the choice of samples for studies of ultrafast magnetic switching.