title: Structural phase transition and magnetic-field effect on the modulated structure in GdBaCo2O5+δ (δ < 0.5).
abstract: We investigated the crystal structures of an ordered perovskite-type cobaltate, GdBaCo2O(5+δ) (δ < 0.5), at elevated temperatures by transmission electron microscopy. Above the magnetic ordering temperature, we observed a first-order structural phase transition between the low-temperature tetragonal 3a(p) × 3a(p) and high-temperature orthorhombic 1a(p) × 2a(p) superstructure phases (where a(p) is the perovskite-unit cell). Upon the application of a magnetic field, an incommensurate phase emerges around the structural phase-transition temperature, which indicates a magnetic-field-induced structural phase transition via no magnetic ordering in the ordered perovskite-type cobaltate.
authors.affiliation: Department of Materials Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Asaka
authors.affiliation: Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Abe
authors.affiliation: Department of Materials Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kudo
authors.affiliation: Department of Materials Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Fukuda
authors.affiliation: National Institute for Materials Science, Tsukuba 305-0044, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kimoto
authors.affiliation: National Institute for Materials Science, Tsukuba 305-0044, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Matsui
authors.affiliation: Advanced Ceramics Research Center, Nagoya Institute of Technology, Tajimi 507-0071, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Ishizawa
authors.affiliation: Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Arima