title: High-temperature magnetic insulating phase in ultrathin La0.67Sr0.33MnO3 films.
abstract: We present a study of the thickness dependence of magnetism and electrical conductivity in ultrathin La0.67Sr0.33MnO3 films grown on SrTiO3 (110) substrates. We found a critical thickness of 10 unit cells below which the conductivity of the films disappeared and simultaneously the Curie temperature increased, indicating a magnetic insulating phase at room temperature. These samples have a Curie temperature of about 560 K with a significant saturation magnetization of 1.2±0.2μ(B)/Mn. The canted antiferromagnetic insulating phase in ultra thin films of n<10 coincides with the occurrence of a higher symmetry structural phase with a different oxygen octahedra rotation pattern. Such a strain engineered phase is an interesting candidate for an insulating tunneling barrier in room temperature spin polarized tunneling devices.
authors.affiliation: Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: Hans
authors.initials: H
authors.lastname: Boschker
authors.forename: Jaap
authors.initials: J
authors.lastname: Kautz
authors.forename: Evert P
authors.initials: EP
authors.lastname: Houwman
authors.forename: Wolter
authors.initials: W
authors.lastname: Siemons
authors.forename: Dave H A
authors.initials: DH
authors.lastname: Blank
authors.forename: Mark
authors.initials: M
authors.lastname: Huijben
authors.forename: Gertjan
authors.initials: G
authors.lastname: Koster
authors.forename: Arturas
authors.initials: A
authors.lastname: Vailionis
authors.forename: Guus
authors.initials: G
authors.lastname: Rijnders