Application of the high temperature series expansions method Green's function theory to the spinel systems: A_xA'_(1-x)B2X4

摘要

The magnetic properties of Mn-Cu ferrites Mn_xCu_(1-x)Fe2O4, have been studied using the many-body Green's function theory (GFT) and high temperature series expansion theory (HTSE). The thermal magnetization and the magnetic susceptibility are given for different values of magnetic field and dilution x. The transition temperature T_C is calculated as a function of Mn concentration. The obtained results are in good agreement with experimental results. The critical exponents associated with the magnetic susceptibility (y) and the correlation lengths (v) have been deduced. The obtained values are comparable to those of 3D Heisenberg model.