Tuning ferromagnetism at interfaces between insulating perovskite oxides

TL;DR

This study uses density functional theory to investigate and identify oxide interfaces, particularly LaAlO3|CaTiO3, that can exhibit robust ferromagnetism, advancing understanding of magnetic properties in insulating perovskite oxides.

Contribution

It demonstrates how interface engineering can enhance ferromagnetism in insulating perovskite oxides, highlighting specific combinations with improved magnetic properties.

Findings

LaAlO3|SrTiO3 is borderline for ferromagnetism.

LaAlO3|CaTiO3 shows robust magnetism with higher Curie temperature.

Interface distortion influences magnetic behavior.

Abstract

We use density functional theory calculations to show that the LaAlO3|SrTiO3 interface between insulating perovskite oxides is borderline in satisfying the Stoner criterion for itinerant ferromagnetism and explore other oxide combinations with a view to satisfying it more amply. The larger lattice parameter of an LaScO3|BaTiO3 interface is found to be less favorable than the greater interface distortion of LaAlO3|CaTiO3. Compared to LaAlO3|SrTiO3, the latter is predicted to exhibit robust magnetism with a larger saturation moment and a higher Curie temperature. Our results provide support for a "two phase" picture of coexistent superconductivity and ferromagnetism.