Ultrafast laser diagnostics and modeling for high-speed recording heads

A comparison of experiment and modeling in high-speed recording heads is gi ven from a study of the dependence of flux rise times on yoke lengths. A br ief overview is given of optical methods for characterizing the response of devices and materials for high data rate recording. Several abilities of t he technique and, in particular, measurements of current and flux rise time s on high-speed writers are presented. A micromagnetic model that takes int o account gyromangetic effects and eddy currents gives calculations that ag ree well with experimental data. Flux rise times are found to decrease with shorter yoke lengths for both unlaminated and laminated heads for a curren t rise time of 0.8 ns.