  AB$_2$O$_4$ normal spinels with a magnetic B site can host a variety of
magnetic and orbital frustrations leading to spin-liquid phases and
field-induced phase transitions. Here we report the first epitaxial growth of
(111)-oriented MgCr$_2$O$_4$ thin films. By characterizing the structural and
electronic properties of films grown along (001) and (111) directions, the
influence of growth orientation has been studied. Despite distinctly different
growth modes observed during deposition, the comprehensive characterization
reveals no measurable disorder in the cation distribution nor multivalency
issue for Cr ions in either orientation. Contrary to a naive expectation, the
(111) stabilized films exhibit a smoother surface and a higher degree of
crystallinity than (001)-oriented films. The preference in growth orientation
is explained within the framework of heteroepitaxial stabilization in
connection to a significantly lower (111) surface energy. These findings open
broad opportunities in the fabrication of 2D kagome-triangular heterostructures
with emergent magnetic behavior inaccessible in bulk crystals.
