Spin Seebeck coefficient enhancement by using Ta50W50 alloy and YIG/Ru interface

Abstract

This paper reports that Ta50W50 alloy has a higher spin Hall angle than that of β-W by measuring the spin Seebeck coefficients for Fe5Y3O12 (YIG)/Ru/Ta50W50 and YIG/Ru/W systems. The spin Seebeck coefficient increased by inserting Ru, and the YIG/Ru/Ta50W50 system achieved 2.4 times the magnitude of spin Seebeck coefficient of the conventional YIG/Pt system although Ru and Ta50W50 have spin Hall angles with opposite signs. Ru seems to recover the spin mixing conductance that is decreased by Ta-W oxidation at its interface with YIG. To enhance the spin Seebeck coefficient, materials having a high spin Hall angle can be combined with materials having a high spin mixing conductance.