Magnon rainbows filtered through phonon clouds

Abstract

The study of heat flow in magnetic insulators is a topic of significant interest in spin caloritronics, especially for understanding the nuanced origins of the spin Seebeck effect (SSE). Recent work by Diniz and Costa (2016 New J. Phys. http://dx.doi.org/10.1088/1367-2630/18/5/052002 18 http://dx.doi.org/10.1088/1367-2630/18/5/052002 ) provides insight into this subject by presenting a microscopic model for the spectral dependence of magnon–phonon interactions in magnetic insulators, which has been a challenging puzzle for decades. Their new paper shows that phonon-mediated magnon-magnon interactions affect the lifetime of magnons differently depending on the magnon wavelength. As a result, low energy magnons transport spin more efficiently, and are more sensitive to applied magnetic fields. These results help explain some unexpected behavior in the SSE recently reported in several experiments.

Keywords

• spin Seebeck effect
• YIG
• magnon–phonon interactions