الفهرس 
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Abstract
In this thesis, we have performed calculation of the magnetic properties of model and real magnetic cubic systems e. g., and compounds. Also magneto-thermal properties of and are studied, in particular the magnetocaloric effect ( ). Mathematica has been used to perform all the calculations we present in this thesis.
A method based on the laws of classical statistical mechanics has been presented to calculate specific magnetic properties of model and real magnetic systems of cubic symmetry. In particular, magnetization curves, magnetic susceptibility, energy and probability landscapes of model systems, of three anisotropy constants of different magnitudes and / or signs, have been investigated. We have applied both energy minimization and our method to the aforementioned systems. We correlate the features of the magnetization curves with those of the energy and probability landscapes.
We report also on the magnetocaloric effect in gadolinium (Gd). The rare-earth element is considered as a benchmark standard for magnetocaloric materials. We performed calculation on a selected rare-earth intermetallic compound, namely , using the molecular field theory of ferromagnetism. This compound has a Curie temperature in the vicinity of room temperature and is, therefore, of practical interest. The magnetization-temperature dependence, magnetic, lattice, electronic and total entropies and specific heats, at different external magnetic fields have been investigated as function of temperature. The magnetocaloric effect i.e. the isothermal magnetic entropy change and the adiabatic temperature change, at different external fields, have been studied.