Quantum Effects for Spintronic Devices Optimization: From perfect multilayered magnetic tunnel junctions to granular magnetic multilayers, new ideas in Spintronics

This work is mainly dedicated to the study of spin dependent transport in magnetic nanostructures. The principal objective is the optimization of the magnetoresistive performance of such structures, in order to built high density Magnetic Random Access Memories (MRAM). Nevertheless, new resistive properties are also found, that could be useful for another type of non-volatile memory device, in this case, Resistive Random Access Memories (ReRAM). The book is basically divided into two parts: the first one considers the theoretical analysis of perfect multilayered magnetic junctions with quantum coherent transport (in the context of Landauer formula), revealing an impressive enhancement of the magnetoresistance, in the so called shallow band regime; the second one is dedicated to the experimental study of magnetic granular multilayers, ten granular Co80Fe20 layers embedded into an insulating Al2O3 matrix, showing interesting resistive and capacitive switching properties, and complemented by a theoretical description of percolation charge transport in these materials (using a mean-field approach).