Spintronic materials and devices: Advances and applications

Abstract

Advances in present-day microelectronics and magnetic data storage devices depend critically on the technological ability to produce device structures of ever-decreasing dimensions. With the typical device dimensions approaching nanometer scale, the materials design parameters are being pushed to their optimum values. Continued device miniaturization is becoming increasingly challenging. There is now a general consensus that the current rate of miniaturization cannot be sustained and new approaches of device fabrication need to be developed. Spintronics is one such approach that is based on the synergetic use of charge and spin dynamics of electrons in certain multifunctional materials. There are various novel device concepts which have been proposed based on this technology, and a few (e.g., read heads for magnetic recorders and nonvolatile memory components) have already found practical applications. The critical step in the functioning of a spintronics device is the injection and detection of spin-polarized carriers at the ferromagnet-semiconductor interface. Despite considerable efforts, effi cient injection of spins into nonmagnetic semiconductors still continues to be a major obstacle in this fi eld. Ferromagnetic metals such as iron and nickel were used in earlier studies for injecting spin-polarized carriers into a semiconducting transport medium. However, in most of the studies the degree of spin polarization of injected carriers was less than a disappointing 1%. In order to overcome this, three different Spintronic Materials and Devices: Advances and Applications