The Anisotropic Classical Chain. Thermodynamic Properties and Phase Diagrams

摘要

The Hamiltonian for the classical model of a one dimensional system containing orthorhombic anisotropy in an external magnetic field is defined, the transfer matrix formalism and the theory of the eigenvalue problem are discussed, and the accuracy of the numerical approach presented is evaluated. Magnetic response functions, correlations, and other thermodynamic variables are considered and experimental results are examined. The chemical and magnetic properties of quasi-one dimensional manganese compounds built up of more or less linear chains of Mn (++) ions were determined and phase diagrams plotted. It is shown that the classical model including orthorhombic anisotropy describes the experimental phase diagrams correctly for all three directions of the magnetic field.