Theoretical study on holographic paramagnetism/ferromagnetism phase transition in Gauss Bonnet gravity

Abstract

In this paper, under the background of four-dimensional Gauss-Bonnet gravity, the changes of the critical temperature, the magnetic moment and other physical quantities in the holographic ferromagnetic model with the Gauss-Bonnet coupling α are studied. Calculations show that the critical temperature decreases as the Gauss-Bonnet coupling α increases, and the magnetic moment is more difficult to form when there is no external magnetic field and the temperature is below the critical temperature. After applying an external magnetic field, the variation of the magnetic susceptibility density with the Gauss-Bonnet coupling α in the high temperature region is consistent with the Curie-Weiss law, and in the low temperature region, a single magnetic field-dominated hysteresis loop appears for different Gauss-Bonnet coupling α. And as the Gauss-Bonnet coupling coefficient α increases, the period of the hysteresis loop becomes longer.