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arXiv · 2103.03765

Ginzburg-Landau theory for the magnetic and structural transitions in La$_{1-y}$(Ca$_{1-x}$Sr$_{x}$)$_{y}$MnO$_{3}$

L. M. León Hilario·A. A. Aligia
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Abstract

We present a phenomenological theory for the ferromagnetic transition temperature, the magnetic susceptibility at high temperatures, and the structural distortion in the La$_{1-y}$(Ca$_{1-x}$Sr$_{x}$)$_{y}$MnO$_{3}$ system. We construct a Ginzburg-Landau free energy that describes the magnetic and the structural transitions, and a competition between them. The parameters of the magnetic part of the free energy are derived from a mean-field solution of the magnetic interaction for arbitrary angular momentum. The theory provides a qualitative description of the observed magnetic and structural phase transitions as functions of Sr-doping level ($x$) for $y=0.25$.

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L. M. León Hilario, A. A. Aligia. 2021-03-05. Ginzburg-Landau theory for the magnetic and structural transitions in La$_{1-y}$(Ca$_{1-x}$Sr$_{x}$)$_{y}$MnO$_{3}$. https://doi.org/10.1088/1361-648x/aaef56

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