  We demonstrate robust interface strain-induced perpendicular magnetic
anisotropy in atomically flat ferrimagnetic insulator Tm3Fe5O12 films grown
with pulsed laser deposition on substituted-Gd3Ga5O12 substrate which maximizes
the tensile strain at the interface. In bilayers consisting of Pt and TIG, we
observe large squared Hall hysteresis loops over a wide range of thicknesses of
Pt at room temperature. When a thin Cu layer is inserted between Pt and TIG,
the Hall hysteresis magnitude decays but stays finite as the thickness of Cu
increases up to 5 nm. However, if the Cu layer is placed atop Pt instead, the
Hall hysteresis magnitude is consistently larger than when the Cu layer with
the same thickness is inserted in between for all Cu thicknesses. These results
suggest that both the proximity-induced ferromagnetism and spin current
contribute to the anomalous Hall effect.
