Spin mixing conductance enhancement by increasing magnetic density

We obtained the spin Seebeck effect enhancement in Y3Fe5O12 (YIG)/Pt system by inserting a very thin Ni80Fe20 at the interface of YIG/Pt. One of important parameters determining the spin Seebeck coefficient is the spin mixing conductance at the interface between magnetic oxide and nonmagnetic metal, and it was theoretically reported that the spin mixing conductance depends on the magnetic density at the interface. However, a ferrimagnetic oxide such as YIG has a small magnetic moment density. In this report, we fabricated YIG (1 mm)/Ni80Fe20 (t nm)/Pt (5 nm) and the spin Seebeck coefficient of t=0.6 nm becomes 2.1 times larger than that of t=0. It is considered owing to improvement of the magnetic moment density and the spin mixing conductance.