Eur. Phys. J. B (2015) 88: 294
https://doi.org/10.1140/epjb/e2015-60409-6

Regular Article

Antiferromagnetic metal phases in double perovskites having microscopic phase segregation due to strong antisite defect concentration

IIT Roorkee, 247667 Roorkee, India

^a e-mail: prabs123@gmail.com

Received: 22 May 2015
Received in final form: 20 August 2015
Published online: 11 November 2015

Abstract

Recently an antiferromagnetic metal phase has been proposed in double perovskites materials like Sr₂FeMoO₆ (SFMO), when electron doped. This material has been found to change from half-metallic ferromagnet to a novel antiferromagnetic metal (AFM) upon La-overdoping. The original proposition of such an AFM phase was made for ordered samples, but the experimental realization of La-overdoped SFMO has been found to contain a substantial fraction of antisite defects. A microscopic chemical phase segregation into alternate Fe and Mo rich regions was observed. In this paper we propose a possible scenario in which an antiferromagnetic metal phase can still be stabilized even in presence of such strong antisite defect concentration and phase segregation, by a novel kinetic energy-driven mechanism. Our results thus provide a plausible explanation to the experimental observations in the La-overdoped regime. Antisite regions can thus give rise to antiferromagnetic metallic phases, although the metal is low-dimensional.