A new class of magnetic materials: Sr₂FeMoO₆ and related compounds

Abstract

Ordered double perovskite oxides of the general formula A₂BB'O₆ have been known for several decades to have interesting electronic and magnetic properties. However, a recent report of a spectacular negative magnetoresistance effect in a specific member of this family, namely Sr₂FeMoO₆, has brought this class of compounds under intense scrutiny. It is now believed that the origin of the magnetism in this class of compounds is based on a novel kinetically-driven mechanism. This new mechanism is also likely to be responsible for the unusually high temperature ferromagnetism in several other systems, such as dilute magnetic semiconductors, as well as in various half-metallic ferromagnetic systems, such as Heussler alloys.