Ultrafast magnetization relaxation of L1(0)-ordered Fe50Pt50 alloy thin film

Abstract

We have investigated the ultrafast magnetization dynamics of L1(0)-ordered Fe50Pt50 thin film by means of a time-resolved magneto-optical Kerr effect measurement. We have found a high Gilbert damping value of alpha similar to 0.26, together with a very high precession frequency of f similar to 85 GHz and the shortest relaxation characteristic time of tau similar to 6.5 ps ever reported. We believe that L1(0)-ordered FePt film with the unique property of a very high precession frequency and the shortest relaxation time will be very useful for the realization of picosecond spin switching. (C) 2011 American Institute of Physics. [doi:10.1063/1.3559845]