Magnetic phase diagram for a non-extensive system: Experimental connection with manganites

TL;DR

This paper explores a nonextensive statistical model for magnetic systems, successfully applying it to manganites to explain their complex magnetic behavior and phase transitions.

Contribution

It introduces a nonextensive statistical framework to analyze magnetic phase diagrams and applies it to manganites, linking theory with experimental magnetization data.

Findings

The model reproduces the temperature and magnetic field dependence of magnetization in manganites.

It demonstrates that manganites exhibit nonextensive magnetic properties.

The phase diagram includes both first and second order phase transitions.

Abstract

In the present paper we make a thorough analysis of a classical spin system, within the framework of Tsallis nonextensive statistics. From the analysis of the generalized Gibbs free energy, within the mean-field approximation, a para-ferromagnetic phase diagram, which exhibits first and second order phase transitions, is built. The features of the generalized, and classical, magnetic moment are mainly determined by the values of $q$, the non-extensive parameter. The model is successfully applied to the case of La$_{0.60}$Y$_{0.07}$Ca$_{0.33}$MnO$_3$ manganite. The temperature and magnetic field dependence of the experimental magnetization on this manganite are faithfully reproduced. The agreement between rather "exotic" magnetic properties of manganites and the predictions of the $q$-statistics, comes to support our early claim that these materials are magnetically nonextensive objects.