Spin Current Driven by Thermal Nonequilibrium

A central goal in spintronics is to develop devices that rely on the transfer of spin rather than charge. In magnetic insulators, magnons, i.e., quanta of collective spin excitations, carry a pure spin current and offer energy efficient information transport and processing. Spin Seebeck effect has emerged as an attractive method for generating spin current due to its simplicity and the ubiquitous presence of thermal gradients. Spin current can be driven by both temperature and magnon chemical potential gradients. Here, we report the spatially resolved measurement of the magnon chemical potential generated by laser heating in the magnetic insulator yttrium iron garnet. With the measured chemical potential, the spin current carried by the nonequilibrium magnons is quantified, and the wavevector and energy range of these nonequilibrium magnons are identified

Date: 
6 Nov 2018
Time: 
2:00pm
Location: 
SHL215
Speaker: 
Xiaoqin (Elaine) Li, University of Texas at Austin
Host: 
Jungfleisch