多层伊辛膜的磁学性质

MAGNETIC BEHAVIOUR OF ISING MULTILAYERS

用变分累积展开 (VCE)方法的一阶近似计算了包括最近邻和次近邻作用的多层伊辛膜的磁学性质 ,导出了自发磁化强度、矫顽力、居里点、奈尔点、顺磁磁化率及分子场系数与层数的关系表达式 。

The magnetic behavior of Ising multilayer system including nearest neighbor and next nearest neighbor interactions is investigated by use of variational cumulant expansion (VCE) method. The formulae for spontaneous magnetization, coercivity, Curie point, Neel point, susceptbility and molecular field parameters responding to the number of layers are deduced and discussed numerically. It is exactly demonstrated that, in 2\|dimensional and 3\|dimensional systems, the spontaneous magnetization 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 temperature. The validity of VCE in high temperature (above the critical point) is explained by the physical meaning of VCE method.