Tuning Ferromagnetism at Interfaces between Insulating Perovskite Oxides

We use density functional theory calculations to show that the LaAlO 3 |SrTiO 3 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 a LaScO 3 |BaTiO 3 interface is found to be less favorable than the greater interface distortion of LaAlO 3 |CaTiO 3 . Compared to LaAlO 3 |SrTiO 3 , 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