CALCULATION OF CRITICAL EXPONENTS γ(L) AND β(L) FOR MAGNETIC THIN FILMS USING VARIATIONAL CUMULANT EXPANSION
Ren Yizhi, Huo Binghai, Ou Jingtian (Institute of Physics, Nankai University, Tianjin, 300071)
Critical temperature for magnetic films with various lattice structures has been calculated by means of variational cumulant expansion (VCE) methad [1,2] . In this paper, the critical exponents γ(L) and β(L) for the magnetic films up to L layers using VCE on the basis of the referenceare calculated and the theoretical results presented here are in agreement with the experimental results given in references[3~5]. For special case of L=1 (two dimensional case), the result obtained is nearly coincidence with the solution by means of other higher accuracy approaches.