  We study the thermal transport in magnetic tunnel junctions. Thermal
gradients across the tunneling barrier appear around the Fowler-Nordheim
tunneling regime, due to the current-induced heat caused by quantum
interference. Both thermovoltage and thermal temperature follow a linear
response with the applied current, which is an evidence for a thermoelectric
effect. By increasing the barrier transparency, the dynamics of thermoelectric
properties is observed with the current. Accordingly, a large range of the
Seebeck coefficient, 10 - 1000 {\mu}V/K, has been obtained in magnetic tunnel
junctions.
