ABSTRACT
With the advent of the so-called magnetic superlattice, it may now be possible to study properties of artificial, periodic layered material structures whose separation between magnetic layers may be on the order of intraatomic distances. Magnetic superlattices are defined as periodic layered structures with alternating layers having different magnetic and=or electrical properties. In order to maintain periodicity in the layered structure, the composition and thickness of each layer is fixed. Precise periodic layered structures have been constructed and this could only be realized with recent improvements in metallization or material deposition techniques. Magnetic properties of layered structures are expected to be different from properties of a single magnetic layer. This difference may be accounted for by the fact that neighboring layers couple to each other via the magnetostatic and exchange interactions. In a microwave environment as we are considering, the internal microwave fields at a point in the layered structure are a function of electromagnetic interferences and magnetic interactions between layers. Hence, the microwave or dynamic properties of a single layer are expected to be different from the properties of layered structures. We develop a transfer function matrix, which relates the microwave fields at the two surfaces of a given magnetic layer. Borrowed from circuit theory, the concept of transfer function is associated with linear systems excited by DC or low-frequency fields. We extend this concept by defining a transfer function matrix for electromagnetic wave propagation in magnetic films or multilayers. Clearly, the total transfer function matrix of a layered structure is the product of single-layer transfer function matrices.
