All our electronic devices work because small particles, called electrons, travel around in conductors and transport charge. As they do so, they collide with impurities in the material which causes heating and makes devices less energy-efficient. Next to charge, electrons also have a property called "spin", of which one can think of as a built-in compass needle of the electron. This property can transport information and to develop applications based on the spin of the electron is the goal of the field called "spintronics". In spintronics, one is concerned with spin transport rather than charge transport.
Recently, experiments have shown that spin transport does not only involve moving electrons. Rather it can also involve magnetic fluctuations, i.e. so-called magnons or spin waves. The theoretical understanding of such experiments is still in its infancy. The goal of the project is to develop the theoretical description of spin transport for situations where this transport is done by spin waves or magnons.
The transport of spin by magnons or spin waves does not involve moving electrons and therefore is expected be more energy-efficient than electronic transport. The longterm goal of this research is to propose devices that are energy-efficient as compared to standard electronic devices.
The project focuses on three candidate material systems: magnetic insulators --- these are magnetic materials that do not conduct electricity, magnetic metals --- magnets that do conduct electrically, and antiferromagnets. The latter materials are magnetic materials of which the magnetic structure is more complex than that of ordinary magnets, so that they do not have a net magnetic moment. Their spin fluctuations, however, can still carry information. In fact, in this project we have shown that they can do so with small dissipation.
