Coercivity engineered magnetic multilayer structures

This research investigates the design and fabrication of digital magnetic structures consisting of multilayers that exhibit uniaxial anisotropy and can adopt one or more of several distinguishable magnetic states. Such digital magnetic structures can be used as a basis for nanoscale memory devices, logic devices, etc. The direction of the magnetisation of each layer corresponds to either a "1" or a "0", thus a binary code can be provided by the magnetic configuration of such multilayer structures. Several criteria need to be fulfilled in order to use these structures for such applications. Firstly, the layers need to be "coercivity engineered" in such a way that they switch independently and at different fields, so called digital switching. This can be achieved by carefully selecting the magnetic materials and their thicknesses and, for example, coupling ferromagnetic layers to antiferromagnetic layers. The magnetic layers need to be separated from each other by non-magnetic layers, and the choice of material and thickness of these layers plays a role as well. Secondly, in addition to switching separately and at different fields, a magnetic code should be preserved at remanence.