TIME-DEPENDENCE AND MECHANISMS OF MAGNETIZATION REVERSAL IN FB-FE-CO FILMS

Measurements have been made of the time dependence of magnetization, u nder constant applied field conditions, of thin films of Tb-Fe-Co allo y. The results have been analyzed using a model in which it is assumed that magnetization proceeds by thermal activation of irreversible swi tching of the magnetic moments of identical elementary volumes. It is assumed that the activation energy for switching, intrinsically the sa me for all elementary volumes, varies according to local interactions. Values of the fluctuation field Lambda are derived and it is found th at for the films examined, Lambda is independent of magnetization M an d the applied field. It is shown that information about the magnetic i nteractions between the elementary volumes, due to exchange and demagn etizing fields, may be derived from graphs of dM/dt vs M. (C) 1996 Ame rican Institute of Physics.