Time-resolved Kerr measurements of magnetization switching in a crossed-wire ferromagnetic memory element

Detailed knowledge of magnetization reversal dynamics in lithographically patterned, micrometer-scale thin film ferromagnetic elements is of basic interest, and is relevant to the development of integrated device applications such as nonvolatile random access memory. We report a time-resolved Kerr microscopy study of the magnetic response of a 1×7 μm2 FeCo element inductively coupled to two crossed write wires. Beginning from a remanent state, switching rates are measured for single pulses of various amplitudes, and for two pulses with fixed amplitude and variable overlap. While using pulse amplitudes near the switching threshold, we observe the magnetization plateauing below the saturation level which we interpret as probabilistic switching caused by thermal fluctuations.