Phase diagrams and critical behaviours of the mixed spin-5/2 and spin-7/2 Ising system

TL;DR

This study uses mean-field theory to analyze the phase diagrams and critical behaviors of a mixed spin-5/2 and spin-7/2 Ising system, revealing complex magnetic phenomena including compensation points and phase transitions.

Contribution

It provides a theoretical analysis of the magnetic properties and phase diagrams of a mixed-spin Ising system using mean-field approximation, highlighting new first-order transition findings.

Findings

Identification of compensation phenomena below critical temperature

Construction of temperature-dependent phase diagrams for unequal sublattice interactions

Discovery of first-order phase transitions in addition to known second-order ones

Abstract

We used mean-field theory based on the Bogoliubov inequality for the Gibbs free energy to examine the magnetic properties of a mixed spin-5/2 and spin-7/2 Blume-Capel ferrimagnetic system. The thermal behaviours of the system magnetization are classified according to the extended N\'eel nomenclature. The system exhibits compensation phenomena where a complete cancellation of sublattice magnetizations is observed below the critical temperature. Temperature-dependent phase diagrams are constructed for the case of unequal sublattice crystal field interactions. Under appropriate conditions, our calculations reveal first-order transitions in addition to second-order ones previously observed in Monte Carlo simulations.