Magnetic systems consisting of a capping layer with uniaxial anisotropy and a recording layer with vertical anisotropy are studied by means of a variational method for a continuum model covering the exchange, anisotropy, and Zeeman energies. The phase transitions between different alignments of magnetization are observed when the thickness of the capping layer and/or the temperature is varied. For the capping layer with in-plane anisotropy, the phase transitions are in second order and the critical behaviors are characterized by a critical exponent 1/2. For the capping layer with vertical anisotropy, the phase transitions are in first order. The analytic expressions of the critical points are presented, in terms of the relevant magnetic constants.
ASJC Scopus subject areas
- Physics and Astronomy(all)