Basic properties of superlattices constructed from ferromagnetic and antiferromagnetic films

Abstract

We present theoretical studies of the properties of superlattices constructed from alternating layers of ferromagnetic and antiferromagnetic films. This paper confines its attention to superlattices in which the antiferromagnet consists of alternating sheets of spins parallel to the interfaces, and the spin alignment within each sheet is ferromagnetic in character. We use localized spin models of each material, and we present studies of the classical ground state of the system, as a function of magnetic field. For the case where the ferromagnetic films each contain an even number of atomic layers, we find a phase diagram which contains four distinctly different phases. We have calculated the spin wave spectrum of each phase, with particular attention directed toward the magnetic resonance spectrum of the superlattice structure. We find a diverse array of spectra, which differ strikingly as microscopic parameters which characterize the superlattice structure as a whole are varied.