  The Spin Hall magnetoresistance (SMR) emerged as a reference tool to
investigate the magnetic properties of materials with an all-electrical set-up.
Its sensitivity to the magnetization of thin films and surfaces may turn it
into a valuable technique to characterize Van der Waals magnetic materials,
which support long range magnetic order in atomically thin layers. However,
realistic surfaces can be affected by defects and disorder, which may result in
unexpected artifacts in the SMR, rather than the sole appearance of electrical
noise. Here, we study the SMR response of heterostructures combining a platinum
(Pt) thin film with the Van der Waals antiferromagnet MnPSe3 and observe a
robust SMR-like signal, which turns out to originate from the presence of
strong interfacial disorder in the system. We use transmission electron
microscopy (TEM) to characterize the interface between MnPSe3 and Pt, revealing
the formation of a few-nanometer-thick platinum-chalcogen amorphous layer. The
analysis of the transport and TEM measurements suggests that the signal arises
from a disordered magnetic system formed at the Pt/MnPSe3 interface, washing
out the interaction between the spins of the Pt electrons and the MnPSe3
magnetic lattice. Our results show that damaged interfaces can yield an
important contribution to SMR, questioning a widespread assumption on the role
of disorder in such measurements.
