Pathways to new magnetic semiconductors and half metals

Abstract

Format

This is a copy of the slides presented at the meeting but not formally written up for the volume.

Abstract

I will discuss theoretical and experimental results pointing to possibly new magnetic materials without resorting to the use of traditional magnetic elements. These ideas will involve the use of special surfaces and interfaces as well as defects. We show that a simple uninteresting oxide like CaO can at least theoretically be turned into a half metallic ferromagnet by introducing Ca vacancies. This mechanism opperates via a molecular analog to Hunds rule coupling and longer range exchange interactions. Polar surfaces and interfaces between polar mismatched layers can develop metallic and magnetic 2 dimensional properties. We also suggest that the use of atomic Hunds rule coupling in O and N which is as large as in the 3d transition metal compounds can be used to generate interesting ferromagnetic materials. Experimental evidence for the fasibility of such materials will also be presented.