Critical Properties of the Models of Small Magnetic Particles of the Antiferromagnet MnF2

TL;DR

This study uses Monte Carlo simulations to analyze the critical behavior of small MnF2 antiferromagnetic particles, considering second nearest neighbor interactions and boundary effects, revealing complexities in identifying phase transition temperatures.

Contribution

It provides new insights into the critical properties of small antiferromagnetic particles by including second nearest neighbor interactions and boundary effects in Monte Carlo models.

Findings

Heat capacity and susceptibility maxima are insufficient to determine transition temperatures.

Boundary effects influence the critical behavior of small particles.

Additional analysis of sublattice magnetization orientation is needed.

Abstract

The static critical behavior of the models of small magnetic particles of the real two sublattice antiferromagnet MnF2 is investigated by the Monte Carlo method taking into account the interaction of the second nearest neighbors. Systems with open boundaries are considered to estimate the influence of the sizes of particles on the pattern of their critical behavior. The behavior of thermodynamic functions in the phase transition region is investigated. The data on the maxima of the temperature dependences of heat capacity and magnetic susceptibility are shown to be insufficient to unambiguously determine the effective temperture of the phase transition in the models of small magnetic particles. This requires an additional investigation of the spatial orientation of the sublattice (sublattices) magnetization vector for the models under study.