Giant magnetoresistance in spin-valve multilayers

The control of magnetism by electric fields is an important goal for the future development of low-power spintronics. Various approaches have been proposed on the basis of either single-phase multiferroic materials or hybrid structures in which a ferromagnet is influenced by the electric field applied to an adjacent insulator (usually having a ferroelectric, piezoelectric, or multiferroic character). The electric field effect on magnetism can be driven by purely electronic or electrostatic effects or can occur through strain coupling. Here we review progress in the electrical control of magnetic properties (anisotropy, spin order, ordering temperature, domain structure) and its application to prototype spintronic devices (spin valves, magnetic tunnel junctions). We tentatively identify the main outstanding difficulties and give perspectives for spintronics and other fields.

Magnetoelectric Devices for Spintronics

Publisher Summary This chapter discusses the physics of giant magneto resistance (GMR). The chapter emphasizes the role of the spin-polarized electronic band structure that is crucial for understanding GMR. The origin of GMR and a simple resistor model has been introduced in the chapter. The experimental data on current-in-the-plane (CIP) GMR in magnetic multilayers, spin valves, dependence of GMR on composition, layer thickness, roughness, impurities, outer boundaries, and temperature have also been discussed in the chapter. The theoretical formulations of GMR within free electron and simple tight-binding models have been reviewed from the semiclassical and quantum mechanical viewpoints. Multiband models for GMR have also been reviewed. The semiclassical and quantum mechanical approaches to GMR within the diffusive limit and the interpretation of selected experimental results have been presented in the chapter.

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Perspectives of giant magnetoresistance

Electrodeposited multilayer films with giant magnetoresistance (GMR): Progress and problems

In this review we discuss conventional methods of performing biological assays and molecular identification and highlight their advantages and limitations. An alternative approach based on magnetic nanotechnology is then presented. Firstly, magnetic carriers are introduced and their biocompatibility and functionalisation discussed, with spotlights on functionalisation via self assembled monolayers and on methods of reducing nonspecific binding. In addition an introduction is provided to the basic physical concepts behind the various types of sensors used to detect magnetic labels. Finally, progress in the field of magnetic biosensors and the outlook for the future are discussed.

S. Nadimi

Papers

Spin-valve effect in soft ferromagnetic sandwiches