Multilayer structures have emerged as a leading research topic and researchers expect that multilayers may lead to interesting artificial materials with novel properties. In this Research News we show that the introduction of interfaces into perovskite oxides can induce a series of novel properties including an unusual positive magnetoresistance, great enhancement of lateral photovoltage in La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3, and an electrical modulation of the magnetoresistance in multi-p-n heterostructures of SrTiO3/La0.9Sr0.1MnO3/SrTiO3/La0.9Sr0.1MnO3/Si. This novel positive magnetoresistance is attributW to the creation of a space charge region at the interface where the spin of No carriers is anti-parallel to that of the carriers in the region far from the interface of manganese oxide in the heterostructures.