Phys. Status Solidi RRL 5, No. 12, A117–A118 (2011) / DOI 10.1002/pssr.201150341

© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

EditorialPreface

Focus on

Spintronics and Spin Physics

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. S. N. Piramanayagam, Jagadeesh Moodera, Russell Cowburn, and Rachid Sbiaa Guest Editors

A118 Preface

© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.pss-rapid.com

stat

us

solid

i

ph

ysic

a rrl

S. N. Piramanayagam received his Ph.D. in 1994 from the Indian Institute of Technology, Bombay (India). After his post-doctoral stint at Shinshu University (Japan), he joined the Data Storage Institute, Singapore in 1999. Since then his research has mainly focussed on magnetic

materials for recording media and spintronics applications. He has published more than 100 papers, and gave invited talks at many major conferences. He is an active volunteer of the IEEE Magnetics Society, and serving the Singapore Chapter continuously from 2004–2011. He is an editorial board member of IEEE Magnetics Letters and three other journals. He has recently published a book under the IEEE-Wiley Press, titled “Developments in Data Storage: Materials Perspective”.

Jagadeesh S. Moodera is a Senior Research Scientist in the Physics Department at MIT leading the group Thin Film Magnetism, Tunneling and Nano Spintronics at the Francis Bitter Magnet Laboratory. He investigates the areas of spin-polarized and spin-filter tunneling, superconductivity, nanospintronics, and topological insulators. Holding

a Ph.D. from the Indian Institute of Technology, Madras, he is a visiting professor at the Applied Physics Department, Technical University of Eindhoven (The Netherlands), as well as at the Institute for Quantum Computing/University of Waterloo (Canada), in addition to being a Distinguished Professor at the Indian Institute of Technology, Chennai. He has published nearly 180 articles including reviews and book chapters, and has given nearly 200 invited talks and colloquia. He is a Fellow of the American Physical Society, and won awards such as the IBM Research Award, the TDK Research Award, the ACI Fellowship from the National Science Foundation, and the Oliver E. Buckley Prize in Condensed Matter Physics from the American Physical Society.

Russell Cowburn obtained his Ph.D. in condensed matter physics from the Cavendish Laboratory of the University of Cambridge in 1996 and was appointed lecturer at Durham University in 2000. In 2005 he took up the Chair in Nanotechnology at Imperial College London from where he returned to the Cavendish

Laboratory as Director of Research in 2010. He was elected a Fellow of the Royal Society in 2010, has founded two start-up companies and has filed around 70 patents. His research interests include spintronics, nanoscale magnetism and laser optics – subjects on which he has published around 100 papers. In recent years his research has been recognised by the awarding of a number of prizes, including the IOP Paterson Medal and Prize, the Hermes International Technology Award and the Degussa Science to Business Award.

Rachid Sbiaa is a research scientist at the Data Storage Institute, Singapore. He obtained his Ph.D. in 1996 from Paris University. After his graduation he worked as a research fellow in the laboratory of magnetism and thin films, CNRS (France). In 2002 he joined TDK Co. (Japan) to work on spintronics

and magnetoresistive read-head sensors. In June 2006 he joined the Data Storage Institute, and has been working on magnetic materials and nanostructures for magnetic recording and spintronics. He published more than 70 publications, one book chapter, and twenty-nine magnetism-related U.S. patents. He is an IEEE member, and is currently acting as treasurer of the magnetics society chapter.