Interface Engineering in La0.67Sr0.33MnO3-SrTiO3 Heterostructures

TL;DR

This study investigates how interface engineering strategies in La0.67Sr0.33MnO3-SrTiO3 heterostructures can eliminate magnetic dead layers and identify oxygen octahedra deformations as the main cause of electrical dead layers.

Contribution

It introduces specific interface engineering methods to distinguish and address the origins of magnetic and electrical dead layers in complex oxide heterostructures.

Findings

Magnetic dead layer can be eliminated by compositional interface engineering.

Electrical dead layer primarily caused by oxygen octahedra deformations.

Removing polar discontinuity affects magnetic but not electrical dead layers.

Abstract

Interface engineering is an extremely useful tool for systematically investigating materials and the various ways materials interact with each other. We describe different interface engineering strategies designed to reveal the origin of the electric and magnetic dead-layer at La0.67Sr0.33MnO3 interfaces. La0.67Sr0.33MnO3 is a key example of a strongly correlated peroskite oxide material in which a subtle balance of competing interactions gives rise to a ferromagnetic metallic groundstate. This balance, however, is easily disrupted at interfaces. We systematically vary the dopant profile, the disorder and the oxygen octahedra rotations at the interface to investigate which mechanism is responsible for the dead layer. We find that the magnetic dead layer can be completely eliminated by compositional interface engineering such that the polar discontinuity at the interface is removed. This, however, leaves the electrical dead-layer largely intact. We find that deformations in the oxygen octahedra network at the interface are the dominant cause for the electrical dead layer.