  The growth of Cr adlayers on the Mn-Ga terminated surface of Ni2MnGa(100) has
been studied in this work. We show formation of islands of epitaxial Cr layer
up to 4 atomic layer heights using scanning tunneling microscopy, while
core-level x-ray photoelectron spectroscopy (XPS) indicates absence of any
intermixing of the adlayer and the substrate. The density of states (DOS) of
the thin Cr layer (2.7 ML) measured by scanning tunneling spectroscopy exhibits
nice agreement with density functional theory (DFT) that establishes that it is
ferromagnetic. In contrast, a thick layer of Cr that also grows epitaxially on
Ni2MnGa(100) is shown to be antiferromagnetic by comparing its XPS valence band
with the DOS for bulk Cr calculated by DFT.
