Temperature Dependence of Resistivity of $Sr_2CoMoO_{6-\delta}$ Films

TL;DR

This study examines how the resistivity and magnetoresistance of Sr2CoMoO6-δ films change with temperature, revealing phase separation and a metal-insulator transition related to ferromagnetic and antiferromagnetic domains.

Contribution

It provides direct experimental evidence of phase separation and a percolative transition in Sr2CoMoO6-δ films, linking magnetic domains to electrical transport properties.

Findings

Coexistence of ferromagnetic metallic and antiferromagnetic insulating domains.

Percolative transition causes metal-insulator transition at T_C.

Direct evidence of phase separation in ordered double-perovskite materials.

Abstract

We investigate the temperature dependence of the resistivity and magnetoresistance of a polycrystalline $Sr_2CoMoO_{6-\delta}$ film deposited on (100)-$SrTiO_3$ substrate prepared by the pulsed laser deposition method. X-ray diffraction, Raman and magnetoresistance results demonstrate clearly the coexistence of a ferromagnetic metallic and an antiferromagnetic (or paramagnetic) insulating domain. Percolative transition between these two phases as the temperature varies, which is believed to induce a metal-insulator transition at around $T_C$, has been directly observed in our measurements of the temperature dependence of the sample resistivity. Thus we have provided new direct evidence that a phase separation scenario also exists in the ordered double-perovskite structure materials.