Magnetic Properties of Diluted Spinels Mg<i><sub>x</sub></i>Ni<sub>1−<i>x</i></sub>Fe<sub>2</sub>O<sub>4</sub> Systems: Are Studied by Green’s Functions and Mean Field Theories

Abstract

Many-body Green's function, and mean field theories have been developed for magnetic systems Mg x Ni 1−x Fe 2 O 4. We apply this theory to evaluate thermal magnetization and magnetic susceptibility for different values of magnetic field and dilution x, by considering all components of the magnetisation when an external magnetic field is applied in (x-z)-plane. The critical temperatures of Mg x Ni 1−x Fe 2 O 4 systems in the range 0 ≤ x ≤ 1 have been deduced. The Green's function results are compared with the results of high temperature series expansion technique, and experimental magnetic measurements.