T-induced changes of magnetization profiles and reversal in exchange-coupled trilayers

Abstract

Thermomagnetic phenomena are investigated in appropriate exchange-coupled trilayers at the basic of a magnetic amplification of the magnetically-induced super-resolution signal used for ultrahigh magneto-optical storage. The changes of the magnetization profiles and reversal behavior between room temperature and the Curie temperature are determined from the mean field theory and a micromagnetic model based on a discontinuous distribution of the magnetization and compared in bi- and trilayers F1/F3 and F1/F2/F3. These multilayers correspond to a TbFeCo layer F1 with perpendicular anisotropy exchange-coupled with either one GdFeCo (F3) or with a double GdFe/ GdFeCo (F2/F3) in-plane magnetic layer. Depending on the magnetic parameters of the in-plane layers associated with appropriate choice of their composition, it is possible to stimulate sequential magnetic reorientation in the layers F2 and F3 at different switching temperatures Ts2 and Ts3 which can induce a dynamic expansion of the magnetic domains in the upper readout layer. © 1999 American Institute of Physics.