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Abstract

It is our pleasure to bring out this Focus Issue on Spintronics and Spin Physics. Spin is an important aspect of physics, ever since the concepts of intrinsic angular momentum by Samuel Goudsmit and George Uhlenbeck, and spin by Wolfgang Pauli were introduced nearly a century ago to explain the experimental observations. In the field of magnetism the electron spin plays the all-important central role. While the study of magnetism has a long history, the function of electron spin in electron transport gained interest and importance only in the recent few decades. This is despite the fact that Mott used two spin-current channels to explain the resistivity behavior in magnetic metals as far back as in the 1930s. Since the eighties, several terms such as magnetotransport and magnetoelectronics, have been used. However, the term spintronics has gained a considerable popularity recently. Professor Albert Fert and Professor Peter Grünberg received their Nobel Prize in 2007 for their discovery of Giant Magnetoresistance (GMR). Read sensors based on the concept of GMR in the late nineties and tunnel magnetoresistance (TMR) since the past several years, are utilized in hard-disk drive products.

The field of spintronics from the early stages of GMR further flourished with the discovery of TMR as well as spin-torque transfer (STT) effect to switch magnetization or to move domain walls. These led to research in the areas of spin injection and manipulation in semiconductors, magnetic random access memory, magnetic logic devices, domain wall memory, and so on. As a result there are plenty of researchers all over the world pushing the frontiers in applied as well as fundamental aspects of the field.

In this Focus Issue we present one Review@RRL on magnetic random access memory (MRAM). This review-type article provides a perspective on materials with a perpendicular magnetic anisotropy. Pentalemma – a challenging situation to meet five different requirements of the MRAM is described in the paper. A review of current materials, potential candidates, and the challenges are presented.

The contributed Letters cover various fields, ranging from fundamentals to device applications; papers on oxide materials discuss topics such as spin-calorics, defect engineering of ferromagnetism in carbon doped ZnO, zinc ferrites with tunable electrical conductivity, and electronic structure of EuO spin filter tunnel contacts. On the topic of metallic films, the Letters cover FePt films for spintronics applications, Co-doped FeSi films, and magnetic tunnel junctions with composite free layers. There are several other papers covering interactions between domain walls and magnetic vortex excitation. On the device front, the papers discuss spin-torque oscillators and domain wall memories.

We hope the Focus Issue will bring valuable knowledge for your research and stimulate more activity in the field of spintronics. We plan to have several special issues on spintronics in the future, as exciting results are appearing recurrently opening new areas of research (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)