Heavy metal deposition temperature tuned spin pumping efficiency control in Permalloy/Tantalum bilayers

Abstract

Spin pumping is a key property for spintronic application that can be realized in ferromagnet/Heavy metal bilayers. Here we demonstrate the possibility of improving spin pumping in Permalloy (Py)/Tantalum (Ta) bilayers through control of Ta heavy metal deposition temperature. Through a combination of structural and ferromagnetic resonance based magnetization dynamics study we reveal the role of Ta deposition temperature in improving spin mixing conductance which is a key parameter for spin pumping across the Py/Ta interface. The results show that by depositing Ta above room temperature a high spin mixing conductance of 7.7 ×1018 m-2 is obtained with α-Ta layer. The results present an understanding of the correlation between heavy metal deposition temperature and interface structure improvement and consequent control of spin pumping in Py/Ta bilayers.