The electronic and magnetic structure at surfaces and interfaces in mixed valence manganites is an active area of research. To study localized properties of interface magnetism in heterostructures we have conducted both current in-plane and current perpendicular-plane measurements in multilayers and trilayer tunnel junctions, respectively. Initial study of the transport in multilayers, consisting of alternating La0.7Ca0.3MnO3 and SrTiO3 with different layer thickness provided information on vertical inhomogeniety in the manganite layers and disordered interfaces. Issues of lattice mismatched strain, structural inhomogeniety were addressed. Trilayer tunnel junctions have been fabricated with the aim of correlating tunneling magnetoresistance to the interface magnetism deduced from multilayer measurements. We describe devices incorporating a novel barrier material which have yielded single domain switchings and very high TMR values above 77 K.