title: Surface-stabilized nonferromagnetic ordering of a layered ferromagnetic manganite.
abstract: An outstanding question regarding the probing or possible device applications of correlated electronic materials (CEMs) with layered structure is the extent to which their bulk and surface properties differ or not. The broken translational symmetry at the surface can lead to distinct functionality due to the charge, lattice, orbital, and spin coupling. Here we report on the case of bilayered manganites with hole doping levels corresponding to bulk ferromagnetic order. We find that, although the hole doping level is measured to be the same as in the bulk, the surface layer is not ferromagnetic. Further, our low-energy electron diffraction and x-ray measurements show that there is a c-axis collapse in the outermost layer. Bulk theoretical calculations reveal that, even at fixed doping level, the relaxation of the Jahn-Teller distortion at the surface is consistent with the stabilization of an A-type antiferromagnetic state.
authors.affiliation: Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA. vnascimento@lsu.edu
authors.forename: V B
authors.initials: VB
authors.lastname: Nascimento
authors.forename: J W
authors.initials: JW
authors.lastname: Freeland
authors.forename: R
authors.initials: R
authors.lastname: Saniz
authors.forename: R G
authors.initials: RG
authors.lastname: Moore
authors.forename: D
authors.initials: D
authors.lastname: Mazur
authors.forename: H
authors.initials: H
authors.lastname: Liu
authors.forename: M H
authors.initials: MH
authors.lastname: Pan
authors.forename: J
authors.initials: J
authors.lastname: Rundgren
authors.forename: K E
authors.initials: KE
authors.lastname: Gray
authors.forename: R A
authors.initials: RA
authors.lastname: Rosenberg
authors.forename: H
authors.initials: H
authors.lastname: Zheng
authors.forename: J F
authors.initials: JF
authors.lastname: Mitchell
authors.forename: A J
authors.initials: AJ
authors.lastname: Freeman
authors.forename: K
authors.initials: K
authors.lastname: Veltruska
authors.forename: E W
authors.initials: EW
authors.lastname: Plummer