title: Origin of interface magnetism in BiMnO3/SrTiO3 and LaAlO3/SrTiO3 heterostructures.
abstract: Possible ferromagnetism induced in otherwise nonmagnetic materials has been motivating intense research in complex oxide heterostructures. Here we show that a confined magnetism is realized at the interface between SrTiO3 and two insulating polar oxides, BiMnO3 and LaAlO3. By using polarization dependent x-ray absorption spectroscopy, we find that in both cases the magnetism can be stabilized by a negative exchange interaction between the electrons transferred to the interface and local magnetic moments. These local magnetic moments are associated with magnetic Ti3+ ions at the interface itself for LaAlO3/SrTiO3 and to Mn3+ ions in the overlayer for BiMnO3/SrTiO3. In LaAlO3/SrTiO3 the induced magnetism is quenched by annealing in oxygen, suggesting a decisive role of oxygen vacancies in this phenomenon.
authors.affiliation: CNR-SPIN, Complesso MonteSantangelo via Cinthia, I-80126 Napoli, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Salluzzo
authors.forename: S
authors.initials: S
authors.lastname: Gariglio
authors.forename: D
authors.initials: D
authors.lastname: Stornaiuolo
authors.forename: V
authors.initials: V
authors.lastname: Sessi
authors.forename: S
authors.initials: S
authors.lastname: Rusponi
authors.forename: C
authors.initials: C
authors.lastname: Piamonteze
authors.forename: G M
authors.initials: GM
authors.lastname: De Luca
authors.forename: M
authors.initials: M
authors.lastname: Minola
authors.forename: D
authors.initials: D
authors.lastname: Marré
authors.forename: A
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authors.lastname: Gadaleta
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authors.lastname: Brune
authors.forename: F
authors.initials: F
authors.lastname: Nolting
authors.forename: N B
authors.initials: NB
authors.lastname: Brookes
authors.forename: G
authors.initials: G
authors.lastname: Ghiringhelli