Competition of magneto-dipole, anisotropy and exchange interactions in composite multiferroics

TL;DR

This study investigates how magneto-dipole, anisotropy, and exchange interactions compete in three-dimensional composite multiferroics, revealing their effects on magnetic states and phase transitions through Monte Carlo simulations.

Contribution

It demonstrates that magneto-dipole interactions do not suppress ferromagnetism but significantly affect the order-disorder transition and hysteresis behavior in composite multiferroics.

Findings

Magneto-dipole interaction does not suppress ferromagnetic states.

Transition from ferromagnetic to superparamagnetic states involves vortex or domain formation.

Temperature hysteresis arises from stable magnetic domains resistant to thermal fluctuations.

Abstract

We study the competition of magneto-dipole, anisotropy and exchange interactions in composite three dimensional multiferroics. Using Monte Carlo simulations we show that magneto-dipole interaction does not suppress the ferromagnetic state caused by the interaction of the ferroelectric matrix and magnetic subsystem. However, the presence of magneto-dipole interaction influences the order-disorder transition: depending on the strength of magneto-dipole interaction the transition from the ferromagnetic to the superparamagnetic state is accompanied either by creation of vortices or domains of opposite magnetization. We show that the temperature hysteresis loop occurs due to non-monotonic behavior of exchange interaction versus temperature. The origin of this hysteresis is related to the presence of stable magnetic domains which are robust against thermal fluctuations.