Final Report Summary - 0MSPIN (Spintronics based on relativistic phenomena in systems with zero magnetic moment)
We proposed research in the area of microelectronic and optoelectronic devices based on antiferromagnets. So far the field has not featured in technology road maps and before our project a viable route for introducing antiferromagnets into practical information technology applications was not even scientifically perceivable. Louis Néel in his 1970 Nobel lecture on the discovery of antiferromagnetism articulated the common view of these magnetic materials as interesting but useless. Indeed, it has been notoriously difficult to control by any practical means antiferromagnetic moments whose direction alternates from one to the other atomic site in the crystal. This has left antiferromagnets over their hundred years history virtually unexploited and only poorly explored, in striking contrast to the thousands of years of fascination and utility of ferromagnetism. By the end of 2014, we came up with a relativistic quantum theory concept opening the route towards efficient electrical control of antiferromagnets. By January 2016 we realized the concept experimentally, as highlighted in our reports and accompanying editorials in Science and Nature journals from early 2016. Our laboratory experiments have been immediately taken one step further by fabricating a demonstrator device and presenting it at the March 2016 plenary and invited sessions of the German and American Physical Societies. The device is connected to a PC USB-port and demonstrates the complete write/store/read functionality of an antiferromagnetic memory with multiple-stable states. We regard this a major scientific breakthrough in the fields of condensed matter physics, magnetism, and spintronics which opens several avenues for future basic research and, we anticipate, also applications. Antiferromagnets offer a unique combination of radiation and magnetic field hardness and operation frequencies reaching THz that might be particularly favorable for developing new types of ultrafast solid state memories.