title: Canted Antiferromagnetism on Rectangular Layers of Fe2+in Polymorphic CaFeSeO.
abstract: From stoichiometric amounts of CaO, Fe, and Se, pure powders and single crystals of quaternary [Formula: see text] can be obtained by solid-state reaction and self-flux growth, respectively. The as-synthesized compound exhibits a polymorphic crystal structure, where the two modifications have different stacking sequences of [Formula: see text] layers. The two polymorphs have similar unit cells but different crystal symmetries (Cmc21and Pnma), of which the former is non-centrosymmetric. Fe is divalent (d6) and high-spin, as proven by X-ray spectroscopy, Mössbauer spectroscopy, and powder neutron diffraction data. The latter two, in combination with magnetic susceptibility and specific heat data, reveal a long-range antiferromagnetic spin order (TN= 160 K) with a minor spin canting. CaFeSeO is an electronic insulator, as confirmed by resistivity measurements and density functional theory calculations. The latter also suggest a relatively small energy difference between the two polymorphs, explaining their intimate intergrowth.
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Straße 40, 01187 Dresden, Germany.
authors.forename: Kwing To
authors.initials: KT
authors.lastname: Lai
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Straße 40, 01187 Dresden, Germany.
authors.forename: Alexander Christoph
authors.initials: AC
authors.lastname: Komarek
authors.affiliation: Institute Laue Langevin , 71 Avenue des Martyrs, 39042 Grenoble Cedex 9, France.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Fernández-Díaz
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Straße 40, 01187 Dresden, Germany.|Department of Electrophysics, National Chiao Tung University , HsinChu 30100, Taiwan.
authors.forename: Pi-Shan
authors.initials: PS
authors.lastname: Chang
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Straße 40, 01187 Dresden, Germany.|University of British Colombia , 2329 West Mall, Vancouver, BC V6T 1Z4, Canada.
authors.forename: Sungjoon
authors.initials: S
authors.lastname: Huh
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Straße 40, 01187 Dresden, Germany.
authors.forename: Helge
authors.initials: H
authors.lastname: Rosner
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Straße 40, 01187 Dresden, Germany.
authors.forename: Chang-Yang
authors.initials: CY
authors.lastname: Kuo
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Straße 40, 01187 Dresden, Germany.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Hu
authors.affiliation: National Synchrotron Radiation Research Centre , Hsinchu 30076, Taiwan.
authors.forename: Tun-Wen
authors.initials: TW
authors.lastname: Pi
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Straße 40, 01187 Dresden, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Adler
authors.affiliation: Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität , 55128 Mainz, Germany.
authors.forename: Vadim
authors.initials: V
authors.lastname: Ksenofontov
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Straße 40, 01187 Dresden, Germany.
authors.forename: Liu Hao
authors.initials: LH
authors.lastname: Tjeng
authors.affiliation: Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Straße 40, 01187 Dresden, Germany.
authors.forename: Martin
authors.identifier: http://orcid.org/0000-0001-7061-3492
authors.initials: M
authors.lastname: Valldor