  The magneto-thermoelectric properties of Heusler compound thin films are very
diverse. Here, we discuss the anomalous Nernst response of Co$_2$MnGa thin
films. We systematically study the anomalous Nernst coefficient as a function
of temperature, and we show that unlike the anomalous Hall effect, the
anomalous Nernst effect in Co$_2$MnGa strongly varies with temperature. We
exploit the on-chip thermometry technique to quantify the thermal gradient,
which enables us to directly evaluate the anomalous Nernst coefficient. We
compare these results to a reference CoFeB thin film. We show that the
50-nm-thick Co$_2$MnGa films exhibit a large anomalous Nernst effect of
-2$\mu$V/K at 300 K, whereas the 10-nm-thick Co$_2$MnGa film exhibits a
significantly smaller anomalous Nernst coefficient despite having similar
volume magnetizations. These findings suggest that the microscopic origin of
the anomalous Nernst effect in Co$_2$MnGa is complex and may contain
contributions from skew-scattering, side-jump or intrinsic Berry phase. In any
case, the large anomalous Nernst coefficent of Co$_2$MnGa thin films at room
temperature makes this material system a very promising candidate for efficient
spin-caloritronic devices.
