Antisite Domains in Double Perovskite Ferromagnets: Impact on Magnetotransport and Half-metallicity

TL;DR

This paper investigates how antisite disorder in double perovskite ferromagnets affects their magnetic and electronic properties, revealing that such disorder suppresses magnetism and half-metallicity but enhances low-field magnetoresistance.

Contribution

It provides the first analysis of spatially correlated antisite disorder's impact on ferromagnetic double perovskites, linking disorder to property changes.

Findings

Antisite domains suppress magnetism and half-metallicity.

Disorder enhances low-field magnetoresistance.

Spatial correlations in disorder are crucial for property modifications.

Abstract

Several double perovskite materials of the form A_2BB'O_6 exhibit high ferromagnetic T_c, and significant low field magnetoresistance. They are also a candidate source of spin polarized electrons. The potential usefulness of these materials is, however, frustrated by mislocation of the B and B' ions, which do not organise themselves in the ideal alternating structure. The result is a strong dependence of physical properties on preparative conditions, reducing the magnetization and destroying the half-metallicity. We provide the first results on the impact of spatially correlated antisite disorder, as observed experimentally, on the ferromagnetic double perovskites. The antisite domains suppress magnetism and half-metallicity, as expected, but lead to a dramatic enhancement of the low field magnetoresistance.