Effect of the Uniform Random External Magnetic Field with Spatio-temporal Variation on Compensation in Ising Spin-1/2 Trilayered Square Ferrimagnet

TL;DR

This study uses Monte Carlo simulations to analyze how a spatio-temporally varying uniform random magnetic field affects compensation points and magnetic behaviors in trilayered Ising ferrimagnets, revealing field-induced phase changes and scaling relations.

Contribution

It introduces a detailed Monte Carlo analysis of the effects of spatio-temporal random magnetic fields on trilayered Ising ferrimagnets, highlighting the emergence and growth of ferrimagnetic islands without compensation.

Findings

Compensation points shift and can vanish with increasing field randomness.

Ferrimagnetic islands without compensation grow with field standard deviation.

Scaling relation for island area as a function of field standard deviation.

Abstract

Trilayered spin-1/2 Ising ferrimagnets are interesting thin systems for compensation phenomenon. In this work, a Metropolis Monte Carlo study is performed on the magnetic and thermodynamic response of such a system on square Bravais lattice, driven by uniform random external magnetic field with spatio-temporal variations. In two distinct configurations, the surface layers are made up of A and the mid-layer is made up of B atoms in a ABA type stacking while in AAB type stacking, the top-layer and the mid-layer is made up of A-atoms while the bottom layer is made up of B-atoms. The magnetic coupling between the like atoms (A-A and B-B) is ferromagnetic while between the unlike atoms (A-B), it is antiferromagnetic. For the time-dependent external uniform random field, the mean is always set to zero and the standard deviation is varied until spin-field energy is comparable to the dominant cooperative energy of the system. The findings show that the observed compensation and critical points shift and steady-state magnetic behaviours shift between N-, L-, P- and Q- etc. type of ferrimagnetic behaviours, depending upon the strength of external uniform random field. The compensation phenomenon even vanishes after crossing a finite threshold of standard deviation of the magnetic field for particular choices of the other controlling parameters. Thus islands of ferrimagnetic phase without compensation appear within the phase area with compensation of field-free case, in the 2D Hamiltonian parameter space. For both the configurations, the areas of such islands even grow with increasing standard deviation of the external field, {\sigma}, obeying a scaling relation of the form: $f ({\sigma}, A({\sigma})) = {\sigma}^{-b} A({\sigma})$ with $b_{ABA} = 1.958 \pm 0.122$ and $b_{AAB} = 1.783 \pm 0.118$ .