Inhomogeneous transport in heteroepitaxial La0.7Ca0.3MnO3/SrTiO3 multilayers

Abstract
We have investigated the electrical transport properties of heteroepitaxial La0.7Ca0.3MnO3(LCMO)/SrTiO3 multilayers; as the LCMO layer thickness was varied from 25 to 2.5 nm, the metallic transition was suppressed and enhanced magnetoresistance extended over low temperatures. The results of transport and magnetic measurements imply a vertically inhomogeneous magnetic structure in the LCMO layers, with magnetically disordered interfaces. Although strain is clearly implicated in this surface disorder, we show that intrinsic magnetic disorder must also be associated with the interfaces.