Spin Diffusion in Double-Exchange Manganites

TL;DR

This paper uses dynamical mean-field theory to analyze spin diffusion in double-exchange manganites, revealing that the spin-diffusion coefficient becomes independent of Hund's coupling in certain parameter regimes, aligning with experimental data.

Contribution

It provides a theoretical analysis of spin diffusion in double-exchange magnets, highlighting the independence of the spin-diffusion coefficient from Hund's coupling in specific conditions.

Findings

Spin-diffusion coefficient is independent of Hund's coupling JH in certain regimes.

Results agree with neutron scattering data and previous high-temperature theories.

Close correspondence between Bethe and hypercubic lattice results.

Abstract

The theoretical study of spin diffusion in double-exchange magnets by means of dynamical mean-field theory is presented. We demonstrate that the spin-diffusion coefficient becomes independent of the Hund's coupling JH in the range of parameters JH*S >> W >> T, W being the bandwidth, relevant to colossal magnetoresistive manganites in the metallic part of their phase diagram. Our study reveals a close correspondence as well as some counterintuitive differences between the results on Bethe and hypercubic lattices. Our results are in accord with neutron scattering data and with previous theoretical work for high temperatures.