Spin transport and dynamics in magnetic insulator/metal systems

In present electronics, mostly the charge of electrons is used as a carrier of information. However, the charge of electrons is not the only property of electrons; each electron also carries angular momentum, called spin. In the past decades, the possibility of using the spin of electrons as a carrier of information has been studied in the research-field called spintronics (abbreviated from spin-based electronics). These investigations lead to first applications, for example magnetic memory (MRAM), where the processing of information is based on spintronic phenomena. Recently, researchers have shown that spin-information also can be transported and stored by an electrically insulating material. This is not possible when using the charge of electrons. Employing an electrically insulating material for spintronic devices opens up the possibility to study purely spin-related phenomena, as charge transport in these materials is prohibited. Eventually this may lead to the development of faster and more energy-efficient devices. The work presented in this thesis shows experimental results on the read-out of magnetic information from an electrically insulating magnetic material, here yttrium iron garnet. Different methods for read-out have been studied, varying from externally exciting the magnetic state (called spin pumping) to full electrical detection, by making use of a newly discovered phenomenon called spin-Hall magnetoresistance. Also a thermal effect, the spin-Seebeck effect (the spin-analogue of the Seebeck effect), is detected. All described experiments increase the understanding of spintronic phenomena combined with electrically insulating magnetic materials, which is a desired step towards the development of a new generation electronics