Magnetism of thin film multilayers: An analogue of interacting platelets

Progress is being made toward manufacturing materials with magnetic properties tailored to the desired application. This result is reached in several steps, which are monitored with different optical techniques such as polarized neutron reflectometry. First, ferromagnetic, metallic films (of Fe, Co, Ni, Gd), a few nanometers thick, are prepared by vapor deposition. Their magnetization can be tuned by changing the chemistry of thickness of the films, and can be biased by embedding the films into a matrix of antiferromagnetic material. Ensembles of metallic films (multilayers of superlattices) can be created, with a magnetic coupling between adjacent layers regulated by the nature and thickness of the spacer. For increasing spacer thickness, the alignment of neighboring magnetic layers switches between a parallel (F) and an opposite arrangement (AF) in an oscillatory manner. In multilayer structures possessing more than one kind of magnetic atom, complex magnetic phase diagrams have been predicted to occur, with properties that are strongly influenced by the presence of a surface. With these characteristics, the phenomenology of magnetic multilayers draws a close similarity to the physics of interacting platelets.