Cationic order-related magnetoresistivity and half-metallicity in bulk Pb2FeMoO6 grown by high pressure synthesis

Abstract

We investigate the electric properties of Pb2FeMoO6 (PFMO), a double perovskite that can be grown in a bulk pure phase only via High Pressure/High Temperature solid-state reaction. The as-obtained PFMO is characterized by a high degree of cationic ordering at the B site between Fe3+ and Mo5+ and a ferrimagnetic transition with TN around 275 K. A semi-metallic to half-metallic transition seems to occur when the ferrimagnetic order arises thanks to the localization of a minority fraction of electrons on the Mo site. In this thermal regime, the system displays asymmetric magneto-resistivity, with selective-polarized carriers promoted by intense negative magnetic fields applied across the Néel transition during the cooling ramp. This cation-ordering related feature vanishes when the Mo-O bond length stabilizes, indicating a strong connection between the magnetic and electrical properties of this compound.