Thermospin phenomena in a quantum dot attached to ferromagnetic leads: Role of asymmetry and alignment

We study the thermospin effects in a system consisting of a quantum dot coupled to ferromagnetic leads. It is shown that sign reversal and oscillation of spin Seebeck coefficient are indicated as a function of device parameters. When the magnetizations of the leads are formed in parallel alignment, the spin Seebeck coefficient and the spin-FOM have their maximum values for the symmetric dot-lead coupling case. However, in the antiparallel case, the optimal device parameters depend mainly on the strength of the magnetic field.