Strain Fields and Critical Phenomena in Manganites I: Spin-Lattice Hamiltonians

TL;DR

This paper develops a theoretical model incorporating strain interactions and spin-lattice coupling to analyze critical phenomena in manganites, successfully predicting critical exponents consistent with experimental data.

Contribution

It introduces a comprehensive Hamiltonian with long-range strain and spin-lattice coupling and applies RG analysis to accurately compute critical exponents in manganites.

Findings

RG-derived critical exponents match experiments

Long-range strain interactions significantly influence critical behavior

The model provides a unified framework for understanding manganite critical phenomena

Abstract

We use a model Hamiltonian to study critical phenomena in manganites. This Hamiltonian includes long-range strain interactions, and a coupling between the magnetic order parameter and the strain field. We perform a perturbative renormalization group (RG) analysis and calculate the static critical exponents, correct to the one-loop level. We compare our RG results with many experiments on doped manganite critical systems. Our theory is in excellent agreement with the experimental values for the critical exponents.