The role of magnetization compensation point for efficient ultrafast control of magnetization in Gd24Fe66.5Co9.5 alloy

The ability of a femtosecond laser pulse to manipulate and reverse the magnetization in a ferrimagnetic Gd 24 Fe 66.5 Co 9.5 thin film was studied experimentally as a function of temperature. For a fixed energy of the laser pulse, the dynamics of magnetization showed different behavior depending on whether the sample temperature was below or above the magnetization compensation point (T M ). The conditions for full ultrafast demagnetization and magnetization reversal were easily achieved below T M , while the same laser excitation caused just 50% demagnetization above T M . This interesting change in magnetization dynamics is qualitatively explained in terms of effective changes in the magnitudes of magnetizations of atomic sublattices. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2013