The discovery, development and future of GMR: The Nobel Prize 2007

One hundred and one years after J J Thomson was awarded the Nobel Prize for the discovery of the electron, the 2007 Nobel Prize for Physics was awarded to Professors Peter Grunberg and Albert Fert for the discovery of giant magnetoresistance ( GMR) in which the spin as well as the charge of the electron is manipulated and exploited in nanoscale magnetic materials. The journey to GMR started with Lord Kelvin who 150 years ago in 1857 made the first observations of anisotropic magnetoresistance and includes Sir Neville Mott who in 1936 realized that electric current in metals could be considered as two independent spin channels. Modern technology also has a significant role to play in the award of this Nobel Prize: GMR is only manifest in nanoscale materials, and the development of nanotechnology growth techniques was a necessary pre-requisite; further, the considerable demands of the magnetic data storage industry to drive up the data density stored on a hard disk fuelled an enormous international research effort following the initial discovery with the result that more than 5 billion GMR read heads have been manufactured since 1997, ubiquitous in hard disks today. This technology drive continues to inspire exploration of the spin current in the field now known as spintronics, generating new ideas and applications. This review explores the science underpinning GMR and spintronics, the different routes to its discovery taken by Professors Grunberg and Fert, the new science, materials and applications that the discovery has triggered and the considerable potential for the future.