Structural Modulation and Phase Transitions in La2CoO4.14 Investigated by Synchrotron X-ray and Neutron Single-Crystal Diffraction - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Inorganic Chemistry Année : 2012

Structural Modulation and Phase Transitions in La2CoO4.14 Investigated by Synchrotron X-ray and Neutron Single-Crystal Diffraction

Résumé

We report a combined synchrotron X-ray and neutron diffraction study on as-grown La2CoO4.14 single-crystal from 10 to 470 K. Unprecedented structural features in terms of a (3 + 2)D incommensurate modulation have been detected and characterized in the Low Temperature Orthorhombic (LTO) phase already at room temperature despite the complex twinning that was unravelled. A new intermediate phase between the LTO and High Temperature Tetragonal (HTT) phases has been observed for the first time (in the range of 413?433 K). The transformation from LTO to this so-called HTLO (High Temperature Less Orthorhombic) phase is associated to a lowering of orthorhombicity and a loss of one modulation vector, yielding a (3 + 1)D incommensurate modulation. Conversely, above 433 K the HTT phase appears as nonmodulated but exhibits a strong dynamic disorder of CoO6 octahedra, which has been characterized in detail by reconstruction of nuclear densities via the Maximum Entropy Method (MEM).

Domaines

Matériaux
Fichier non déposé

Dates et versions

hal-00802244 , version 1 (19-03-2013)

Identifiants

Citer

Olivier Hernandez, Werner Paulus, Juerg Schefer, Carmelo Prestipino, Loïc Le Dréau, et al.. Structural Modulation and Phase Transitions in La2CoO4.14 Investigated by Synchrotron X-ray and Neutron Single-Crystal Diffraction. Inorganic Chemistry, 2012, 51 (18), pp.9789-9798. ⟨10.1021/ic301165a⟩. ⟨hal-00802244⟩
126 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More