Landau Theory of the Phase Transitions in Half Doped Manganites: Interplay of Magnetic, Charge and Structural Orders

TL;DR

This paper develops a Landau theory to explain the complex interplay of magnetic, charge, and structural orders during phase transitions in half-doped manganites, providing a unified understanding of their behaviors.

Contribution

It introduces a comprehensive Landau theoretical framework that captures the phase transition mechanisms and structural behaviors in half-doped manganites.

Findings

Accounts for structural and thermodynamical behaviors

Explains the origin of incommensurate orbital order

Provides a unified picture of phase transition scenarios

Abstract

The order parameters of the magnetic, charge and structural orders at half-doped manganites are identified. A corresponding Landau theory of the phase transitions is formulated. Many structural and thermodynamical behaviors are accounted for and clarified within the framework. In particular, the theory provides a unified picture for the scenario of the phase transitions and their nature with respect to the variation of the tolerance factor of the manganites. It also accounts for the origin of the incommensurate nature of the orbital order and its subsequently accompanying antiferromagnetic order.