Study of magnetocaloric effect and magnetic properties of the nano-graphene bilayer with RKKY interactions of a mixed spins S = 3/2 and σ = 3: a Monte Carlo simulation

In this study, we have used Monte Carlo simulations that explain the magnetic properties and magnetocaloric effect of a nano-graphene bilayer separated by non-magnetic layers with mixed spin 3/2 and 3 with RKKY (Ruderman-Kittel-Kasuya-Yosida) exchange coupling. We present and discuss ground state phase diagrams that have been found. Also, the reduced critical temperature is obtained for several values of the number of non-magnetic layers (NM). The system can exhibit a phase transition from the ferromagnetic to the paramagnetic phase at a reduced critical temperature. The effect of the parameter NM, the reduced exchange interactions (S–S), (σ−σ), and the reduced crystal field on the total magnetizations and the established hysteresis loops are investigated. Specific heat, specific heat change, thermal magnetization dM/dT, and magnetic entropy changes as a function of the temperature for various reduced external magnetic fields were investigated in detail. Finally, we report the influence of different values of reduced magnetic field h/Jsσ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$h/J_{s\sigma }$$\end{document} on the relative cooling power.