Ferromagnetic resonance spectra of Py deposited on (Bi1-xSbx)2Te3

Abstract

We measure ferromagnetic resonance spectra of sputtered Py (20 nm) on (Bi1-xSbx)2Te3 (∼50 nm, x = 0-1) grown by molecular beam epitaxy. The linewidths of the spectra for Py on (Bi1-xSbx)2Te3 are much broader than that of Py directly deposited on a flat Si/SiO2 substrate. We find that the broadening results from spin pumping as well as inhomogeneity in Py induced by surface roughness of underneath (Bi1-xSbx)2Te3.