  We study a system composed of a quantum dot in contact with ferromagnetic
leads, held at different temperatures. Spin analogues to the thermopower and
thermoelectric figures of merit are defined and studied as a function of
junction parameters. It is shown that in contrast to bulk ferromagnets, the
spin thermopower coefficient in a junction can be as large as the Seebeck
coefficient, resulting in a large spin figure of merit. In addition, it is
demonstrated that the junction can be tuned to supply only spin current but no
charge current. We also discuss experimental systems where our predictions can
be verified.
