Thickness Dependent Spin Pumping Effects in La$_{0.7}$Sr$_{0.3}$MnO$_{3}$/Platinum Bilayer Film

Abstract

The inverse spin-Hall effect (ISHE) which predicts the transferring of spin current to electrical voltage has received extensive attention due to its experimental realization in the ferromagnetic(FM)/paramagnetic(PM) bilayer systems. The ISHE induced spin voltage is measured via the technique of spin pumping in association with a mechanism of driving the spin angular momentum from the FM layer into the PM layer via ferromagnetic resonance. Among many novel metals, platinum (Pt) is widely used as PM layer because of its strong spin-orbit coupling. In this work, we study the FM-thickness dependence of ISHE in two bilayer films, La0.7Sr0.3MnO3(10 nm)/Pt(10 nm) and La0.7Sr0.3MnO3(23 nm)/Pt(10 nm). Our experimental results show that the ISHE voltage is larger in the film with 10 nm-FM layer, and the fitting results indicate that there may be a direct relation between the magnitude of ISHE voltage and the damping constant of FM layer.