Insulator-metal transition induced by interlayer coupling in La0.6Sr0.4MnO3/SrTiO3 superlattices - art. no. 064429

The electronic and magnetic properties of perovskite superlattices composed of five unit-cell layers of ferromagnetic metal La0.6Sr0.4MnO3 and nonmagn etic band insulator SrTiO3 with varying layer thickness have been systemati cally investigated. The superlattices have well-defined periodic stacking w ith no sign of interlayer diffusion. The spin canting at the interfaces in La0.6Sr0.4MnO3 layers manifests itself as a suppressed magnetization and hu ge magnetoresistance subsisting to low temperature. The transport propertie s show a clear crossover from insulating to metallic perhaps by an increase in the interlayer electron hopping through SrTiO3 layers when the SrTiO3 l ayer thickness is reduced. This crossover is also discerned in the infrared optical spectra as the filling of absorption in the low-energy region.