Study Of Physical Properties On Molecular-Based Magnet

As a new soft magnetic material, molecule-based magnetic materials become a new branch of science, which has been studied by many chemist, physicist and biologist. Molecule-based magnetic materials are defined as useful material of molecular framework, which is made up of molecular or charged molecules. As magnetic materials, molecule-based magnets has characters of small, low density, structural diversity and easy-to-composite molding process, that is material of spacecraft, microwave absorption of stealth, electromagnetic shielding and information storage. The molecule-based magnetic material AFe^â…¡Fe^â…¢(C₂O₄)₃[A=N(n-C_nH_2n+1)₄, n=3-5] is described by a mixed spin 2 and spin 5/2 Ising ferromagnetic system with a layered honeycomb lattice.In this paper, properties of the molecule-based magnets have been studied in detail, within Ising model and the framework of effective-field theory with correlations. The effective-field theory with correlations of the mixed spin 2 and 5/2 molecular-based magnetic materials Ising model has been introduced in the transverse field and longitudinal field. The equations for magnetization, initial susceptibility, internal energy and specific heat are given. The numerical results have also been analyzed and discussed as follows: The exchange coupling, the sublattice anisotropy, the transverse field, longitudinal field and temperature play important role in the system. The transition temperature and compensation temperature decrease with increasing of the transverse field. The transverse field makes the magnetization decrease, corresponding to the change of the spin configurations at the ground states. It is thought that in a certain sense, the temperature has an effect similar to that of the transverse field, namely, both of them make the magnetization decrease. The transverse field alters the spin configurations at the whole temperature range, but the effect of the temperature becomes more pronounced only at mediate/high temperatures. The longitudinal field alters the spin configurations, so magnetization increases with the increasing longitudinal field. At low temperature, magnetization is mainly effected by the temperature and crystal field, but the effect of the longitudinal field becomes more pronounced at high temperatures. Internal energy increases with the decreasing of the longitudinal field. The transition temperature decreases with the increasing of the longitudinal field.