The 2007 Nobel Prize
in Physics: The discovery of giant magnetoresistance
Dr Michael Smith
University of Queensland
Abstract
As a member of the UQ condensed matter physics group with current interest in magnetotransport,
I want to recognize the achievement of
Fert and Grünberg by talking about the physics of GMR and the impact of its discovery on current
condensed matter research.
Speaker Profile
The 2007 Nobel Prize in Physics was
awarded to Albert Fert and Peter Grünberg
for their independent experimental discoveries of giant magnetoresistance (GMR)
in 1988. GMR is a property of
nanostructured stacks of magnetic metal layers: the electrical resistance of
these systems undergoes a large (giant) change when subjected to a magnetic
field. This makes devices based on
GMR highly sensitive to variations in magnetic field strength and direction, the
key to their utility in read-out heads of computer hard drives.
While making possible the dramatic reduction in hard-drive size over the
last decade, the discovery of GMR also sparked an explosion of research into
spin-dependent transport and the new field of spintronics.
Dr Smith completed his Ph.D in condensed matter theory at the University of
Toronto, Canada, in 2005. His research focused on transport properties of
high-temperature superconductors, in particular quasiparticle excitations in the
superconducting state. A highlight was the resolution of a puzzling experimental
finding that electrons in cuprate superconductors (in the field-induced normal
state) appear to carry charge without carrying any heat. Following this he spent
a couple of years working at the National Synchrotron Research Center, the Thai
synchrotron facility in Nakhon Ratchasima, Thailand, doing ab-initio simulations
of defects in wide band gap semiconductors and their x-ray absorption properties
in collaboration with theorists at NREL in Colorado. In August 2007 he began a
postdoc period at the University of Queensland with Ross McKenzie, to work on
quantum magnetotransport in layered metals, including organics and
unconventional superconductors. Most recently they have been studying transport
properties of heavy Fermion materials near their metal-magnetic transition. The
2007 Nobel Prize was announced shortly after Dr Smith began at UQ and, since his
research interests had some overlap with the field of the prize-winning work, he
was asked to give a summary talk about the background to and the physics of GMR.