Effective methodology for calculation of magnetic properties of atomic systems in ordered state and around phase transition temperature

摘要

We present main algorithms of new software application developed to calculate magnetic, spectral and calorimetric properties of materials under Crystal Electric Field (CEF) and Mean Field Approximation paradigm. The novelty of our approach lies in the automatic construction of Hamiltonian matrices and computation of true 3-dimensional properties of the material in wide range of temperatures also around the phase transition temperature. User defined calculation rules as real or complex matrices and two calculation spaces (|JJ_z> or |LSL_zS_z>) to define interactions, utilize single diagonalization procedure in all cases. Our software predicts thermal dependent properties of materials in isostructural series of compounds, such as: magnetic moment in ordered state, paramagnetic susceptibility, specific heat, entropy and absorption spectra. Calculated properties are closely related to local symmetry of crystal surrounding of paramagnetic ion. Obtained angular momentum coordinates of paramagnetic ions makes it possible to calculate anisotropy coefficients as a result of dynamic calculations using Mean Field Approximation scheme.