Magnon spintronics

Abstract

Spintronics is an emerging and very active field of science and technology that is devoted to the investigation of basic phenomena and device application based on the electron spin in addition to its charge. Spintronic devices are already used in high-density nonvolatile magnetic storage, and intense research efforts are under way worldwide to develop new functionalities for transport and processing of information not available in conventional electronics. In this chapter we study topics of spintronics in which magnons play a direct role. Initially we introduce the concept of spin current in nonmagnetic metals, which is essential to understand the spin Hall effect, the Rashba–Edelstein effect, and other spintronics phenomena. Then we present the phenomenon of spin transfer torque in magnetic multilayers and study the excitation of magnons by electric currents. Next we study the spin pumping effect, one of the most important in spintronics. In the following section we study the concepts of magnon accumulation and magnonic spin currents, and derive their important governing equations. Finally, we study the spin Seebeck effect in magnetic insulators that is based on the magnonic spin current.