Unconventional scaling and significant enhancement of the spin Seebeck effect in multilayers

Spin Seebeck effects (SSEs) have been investigated in highly crystalline magnetic multilayer [Fe3O4/Pt]n films. Voltage as well as power generated by the SSE were found to be significantly enhanced with increasing the number of layers n. This voltage enhancement defies the simple understanding of the SSE and suggests that spin current flowing between the magnetic layers in the thickness direction plays an important role in multilayer SSE systems and the observed voltage enhancement.