Growth and magnetoresistive properties of (LaMnO3)m(SrMnO3)n superlattices

Abstract

Artificial (LaMnO3)m(SrMnO3)n superlattices, n/(m+n)=0.26, were grown with pulsed-laser deposition, and the superlattice period Λ was varied. Their structural characteristics were investigated using x-ray diffraction and electron microscopy. When Λ<ap (perovskite lattice parameter), bulk-like properties of La0.74Sr0.26MnO3 are obtained: TMI (metal-to-insulator transition temperature) ≈Tc (Curie temperature) ≈345 K and −MR (magnetoresistance) ≈100%. Increasing Λ (to 21 ap) leads to a decrease in the Tc, the low-temperature magnetization, the magnetoresistance, and the TMI—eventually becoming insulating at low temperatures. These effects can be explained by Mn3+/Mn4+ separation arising from the artificially induced La/Sr order.