Structure of V–MgO and MgO–V interfaces

V and MgO films of various thicknesses were deposited on the (001)MgO surface of a MgO substrate by molecular beam epitaxy to prepare two different interfaces: V[sbnd]MgO and MgO[sbnd]V. Cross-sectional specimens were prepared from … V/MgO/V/MgO multilayers and the V[sbnd]MgO and MgO[sbnd]V interfaces were investigated from different directions by conventional and high-resolution electron microscopy (HREM). V deposited on the MgO substrate had a V[sbnd]MgO interface that changed from coherent to semicoherent above a critical film thickness much larger than the predicted value. MgO deposited on this V exhibited a coherent MgO[sbnd]V interface for small film thicknesses, but an interfacial spinel compound formed for larger thicknesses of the MgO film. A comparison of simulated and experimental HREM images of the V[sbnd]MgO interface indicates that the V atoms are located directly on top of the Mg atoms.