Charge states and magnetic ordering in LaMnO3/SrTiO3 superlattices

TL;DR

This study explores how charge doping and magnetic order vary in LaMnO3/SrTiO3 superlattices with different layer thicknesses, revealing doping levels are consistent across thicknesses while magnetic stability decreases with thinner layers.

Contribution

It provides new insights into the relationship between layer thickness, doping, and magnetic stability in LaMnO3/SrTiO3 superlattices.

Findings

LaMnO3 layers are slightly doped regardless of thickness.

Doping levels are similar across different layer thicknesses.

Magnetic ordering stability decreases with thinner LaMnO3 layers.

Abstract

We investigated the magnetic and optical properties of [(LaMnO3)n/(SrTiO3)8]20 (n = 1, 2, and 8) superlattices grown by pulsed laser deposition. We found a weak ferromagnetic and semiconducting state developed in all superlattices. An analysis of the optical conductivity showed that the LaMnO3 layers in the superlattices were slightly doped. The amount of doping was almost identical regardless of the LaMnO3 layer thickness up to eight unit cells, suggesting that the effect is not limited to the interface. On the other hand, the magnetic ordering became less stable as the LaMnO3 layer thickness decreased, probably due to a dimensional effect.