MAGNETIC BEHAVIOUR OF ISING MULTILAYERS
多层伊辛膜的磁学性质

The magnetic behavior of Ising multilayer system including nearest neighbor and next nearest neighbor interactions is investigated by use of variational cumulan t expansion (VCE) method. The formulae for spontaneous magnetization, coercivity , Curie point, Neel point, susceptbility and molecular field parameters respondi ng to the number of layers are deduced and discussed numerically. It is exactly demonstrated that, in 2-dimensional and 3-dimensional systems, the spontaneous m agnetization calculated by first order of the VCE is the same as the results of mean field theory. This means that the first order of VCE is valid in low temper ature. The validity of VCE in high temperature (above the critical point) is exp lained by the physical meaning of VCE method.