We introduce and study a magnetocaloritronic circuit element based on a
domain wall that can move under applied voltage, magnetic field and temperature
gradient. We draw analogies between the Carnot machines and possible devices
employing such circuit element. We further point out the parallels between the
operational principles of thermoelectric and magnetocaloritronic cooling and
power generation and also introduce a magnetocaloritronic figure of merit. Even
though the magnetocaloritronic figure of merit turns out to be very small for
transition-metal based magnets, we speculate that larger numbers may be
expected in ferromagnetic insulators.Comment: Submitted to "Special issue: Caloritronics" in Solid State
Communication