2013 Swan Medal of the Institute of Physics

Dr Stuart S P Parkin, IBM Research – Almaden. For his discoveries of the underlying physics and of novel device architectures that have established the field spintronics.

Stuart Parkin is one of a very special band of scientist/engineers whose scientific discoveries have generated technologies that had changed, for the better, the way we live. He has an unparalleled record of discovering deep science and bringing it to realizable technology. His is the seminal work that translated the first seeds in the field of spintronics into its major standing today, both as physics and also as technology. Stuart had a very distinguished early career at IBM San Jose in the field of superconductivity, both organic and also the cuprates. He then moved to work on thin film magnetism, picking up on the discovery of giant magnetoresistance, GMR, by Fert and Grunberg. Stuart took a novel and high-risk approach, preparing samples by the relatively simple method of successive sputtering of metal layers. This allowed him to explore much of the periodic table, thus to find both the optimum structures and also to find the core physics behind the phenomenon (magnetic scattering at the metal-metal interfaces). Through Stuart’s involvement in IBM’s storage business, his GMR inventions were remarkably quickly implemented in hard disk read heads, producing a huge increase in storage density. Indeed it is through Stuart’s discoveries of the underlying physics and identification of possible device architectures, that the scientific field of ‘spintronics’ was created.

Stuart has since made the crucial breakthroughs in the manufacturing of magnetic tunnel junctions (with a thin insulator between metal layers) that improves sensitivity of the GMR effect, and demonstrated that this allows the manufacturing of static RAM using magnetic field writing and his tunnel junctions deposited on CMOS for reading. This technology has been taken to practical application, but has also improved GMR read-head performance for hard disk drives and is now universally adopted in current manufactured hard drives. He went on to devise and demonstrate electrical (rather than magnetic) switching of magnetic domains, allowing in principle a huge breakthrough in static RAM performance. This depends on controlled injection of spin-polarised electrons in what Stuart terms a ‘magnetic race track memory’ and is a stunning intellectual achievement, harnessing fundamental new science to very ingenious, practical and manufacturable technology.