Hexagonal core-shell structure nanowire with high spins of spin-3/2 and spin-5/2

TL;DR

This study investigates the magnetic properties and phase transitions of a hexagonal core-shell nanowire with mixed high spins using the mean-field approximation, revealing various transition types and compensation phenomena.

Contribution

It introduces a detailed analysis of a hexagonal Ising nanowire with mixed high spins and explores the effects of interactions and external fields on its phase behavior.

Findings

Model exhibits only second-order phase transitions at zero field for non-negative crystal fields.

First- and second-order phase transitions occur under non-zero external magnetic fields.

The system shows compensation temperatures across different field conditions.

Abstract

The magnetic properties and hysteresis loops for the hexagonal Ising nanowire (HIN) with a core-shell structure consisting of mixed spins with the core spin being spin-5/2 and the shell spins being spin-3/2 are studied. The Blume-Capel model is considered by using the mean-field approximation (MFA) based on the Gibbs--Bogoliubov inequality for free energy. The impact of different bilinear interaction parameters ($J_{cc}, J_{ss}, J_{cs}$) between the core, shell, and core and shell spins, respectively, including the crystal ($D_c, D_s$) and external magnetic fields ($h=h_c=h_s$) at the core and shell sites, are taken into consideration. In order to obtain phase diagrams on various planes, the thermal changes of the net, core, and shell magnetizations are investigated for various values of our system parameters. It is discovered that the model exhibits only second-order phase transitions when $h=0.0$ for $D$ greater or equal to zero, first- and second-order phase transitions for $h\neq0.0$ and compensation temperatures for all $h$.