The observation of a sizable anomalous Hall effect in magnetic materials with vanishing magnetization has renewed interest in understanding and engineering this phenomenon. Antiferromagnetic
antiperovskites are one of emerging material classes that exhibit a variety of interesting properties
owing to a complex electronic band structure and magnetic ordering. Reports on the anomalous
Nernst effect and its magnitude in this class of materials are, however, very limited. This scarcity
may be partly due to the experimental difficulty of reliably quantifying the anomalous Nernst
coefficient. Here, we report experiments on the anomalous Nernst effect in antiferromagnetic antiperovskite Mn3NiN thin films. Measurement of both the anomalous Hall and Nernst effects using
the same sample and measurement geometry makes it possible to directly compare these two effects
and quantify the anomalous Nernst coefficient and conductivity in Mn3NiN. We carefully evaluate
the spatial distribution of the thermal gradient in the sample and use finite element modeling to
corroborate our experimental results.