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IEEE Magnetics Society
Santa Clara Valley Chapter
Meeting Presentation Summary

Tuesday, September 20th, 2011

Western Digital, 1710 Automation Parkway, San Jose, CA
Directions and Map
Cookies, Conversation & Pizza too at 7:00 P.M.
Presentation at 7:30 P.M.

Turning insulators into metals

Stuart S.P. Parkin, Ph.D.
IBM Almaden Research Center


     What makes a metal a “metal” has been the subject of considerable interest over the past several decades, from both a fundamental science as well as a technology perspective. Many binary and complex insulating oxides form reversible metallic states by the application of electric fields. This phenomenon forms the basis of a class of non-volatile resistive random access memories. We show that one of the simplest binary oxides – MgO – can be used as a resistive memory element when small amounts of oxygen are replaced by nitrogen. At the same time we show that nitrogen doped MgO exhibits ferromagnetism with magnetic ordering temperatures of up to ~600 K.

     Turning insulating N doped MgO into a metal involves the electric field induced movement of atoms, most likely to form conducting metallic filaments, which subsequently can be disrupted so as to revert the material to its insulating state. Perhaps of greater interest are cases where electric fields can convert insulators to metals purely electronically (without the motion of atoms). We discuss, in particular, the case of thin films of vanadium dioxide and vanadium sesquioxide. We show that in these cases electric fields can be used to form volatile metallic states on time scales as low as a few hundred picoseconds. We discuss the dependence of this phenomenon on the strength of the electric field and show that our results are consistent with an electric field induced creation of carriers within a Mott-Hubbard model.


Photo of AUTHOR Stuart S.P. Parkin, Ph.D. is an IBM Fellow and Manager of the Magnetoelectronics group at the IBM Research - Almaden, San Jose, California and a consulting professor in the Department of Applied Physics at Stanford University. He is also director of the IBM-Stanford Spintronic Science and Applications Center, which was formed in 2004. He received his BA and PhD degrees from the University of Cambridge and joined IBM as a postdoctoral fellow in 1982, becoming a permanent member of the staff the following year. Parkin's research interests have included organic superconductors, high-temperature superconductors, and, most recently, magnetic thin film structures and spintronic materials and devices for advanced sensor, memory, and logic applications. He is a Fellow of the Royal Society, the American Physical Society, the Institute of Physics (London), the Institute of Electrical and Electronics Engineers, and the American Association for the Advancement of Science.



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