Magnetism at transition metal surfaces

Abstract

Transition metal surfaces are important technologically as good catalysts. Interfaces and superlattices of magnetic transition metals also hold the promise of new device applications. The properties of surfaces and interfaces are determined by the local band structure which is directly related to the magnetisation density. One of the fundamental problems of surface magnetism is, therefore, to determine the ground-state surface perturbation to the magnetisation density. After a somewhat turbulent history, the ground-state surface problem is now well understood. The current status of the theory and detailed results for Fe and Ni surfaces are reviewed in the first part of the article. Experimental methods for magnetic surfaces are also discussed, with particular emphasis on the interpretation of data for Fe and Ni, which is still in some cases controversial. The other two central questions addressed in this review concern the nature of magnetic excitations at surfaces and the way the magnetisation disorders near a surface at finite temperatures.