Spin caloritronics in magnetic metals and insulators

The connection between heat and electricity is called thermoelectricity and was discovered long ago. It induces an electrical current when applying a temperature difference across an electrical conductor or leads to heating/cooling when sending an electrical current through the interface between two conductors. The research discussed in this thesis looks at how these thermoelectric effects behave in magnetic metals. We show that an interface between a magnetic and a non magnetic metal is cooled when sending in a magnetic polarized current. Furthermore we have demonstrated that it is possible to make a nanoscale heat switch by switching two magnetic layer, separated by a thin layer of copper. Thermoelectric effects are not observed in electrical insulators as no electrical current can flow. However, it is possible to observe magnetic thermoelectric effects because the magnetic moments of the electrons are able to interact. We show for the first time that by sending such a 'magnetic current' into a magnetic insulator heating or cooling is induced, depending on the magnetization direction. With the help of a computer model we are able to replicate the physical effects in our measurements to quantify what is happening even better