Spin pumping into a partially compensated antiferromagnetic/paramagnetic insulator

Abstract Spin pumping from a metallic ferromagnet (FM) into an insulating antiferromagnet has been studied across the magnetic phase transition by means of temperature-dependent, broad-band ferromagnetic resonance (FMR) experiments. A set spin heterostructures consisting Permalloy (Ni$_{80}$Fe$_{20}$) as FM and Zn$_{1-x}$Co$_{x}$O with $x=0.3, 0.5$ $0.6$ (Co:ZnO) partially compensated antiferromagnetic insulator used for which previous experiments have already pointed out possibility existence spin-pumping. The present allow to reliably separate various contributions temperature-dependent Gilbert damping parameter FMR line-width. careful analysis obtained data demonstrates significant increase temperature-dependence $\alpha(T)$ around Co:ZnO extends up room temperature, confirming fluctuating sink antiferromagnetic/paramagnetic insulator.