  Thermal transmission in a molecular transistor with fully spin-polarized
electrodes subjected to a temperature gradient is considered. The problem has
been solved by using density matrix method in perturbation approach over small
tunneling width. It has been found that due to the vibronic effects spintronic
molecular transistor is characterized by negative differential
thermoconductance. It has been demonstrated that in the dependence of
thermopower $S$ on the detuning energy there is an increased number of points
of change of the sign and magnitude of $S$ comparing with that of conventional
molecular transistor. Optimal parameters, that provide the highest
thermoelectric power at maximum efficiency $P_{me}$ for spintronic molecular
transistor, have been found. The dependences of the figure of merit $ZT$ and
$P_{me}$ on temperature and an external magnetic field have been calculated and
the influence of Coulomb interaction on the thermolelectric properties has been
studied. It has been revealed, that for non-zero Coulomb interaction more handy
regime of thermoelectric device develops, characterized by continuous region of
external magnetic fields, which provide high values of thermoelectric power.
