Structural phase transition in cobalt oxyfluoride Co3Sb4O6F6 observed by high-resolution synchrotron and neutron diffraction. (April 2022)

• Record Type: Journal Article
• Authors: Shimono, Seiya; Ishibashi, Hiroki; Nagayoshi, Yusuke; Ikeno, Hidekazu; Kawaguchi, Shogo; Hagihala, Masato; Torii, Shuki; Kamiyama, Takashi; Ichihashi, Katsuya; Nishihara, Sadafumi; Inoue, Katsuya; Ishii, Yui; Kubota, Yoshiki
• Is Part Of: Journal of physics and chemistry of solids. Volume 163(2022)
• Publication Date: 2022-04
• Subjects: Structural phase transition -- Cobalt oxyfluoride -- X-ray diffraction -- Neutron diffraction; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2021.110568
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: A structural transition was observed in non-centrosymmetric oxyfluoride Co3 Sb4 O6 F6 at T S ∼180 K from a cubic phase ( I 4 ‾ 3 m ) to a c > a tetragonal phase ( I 4 ‾ ), through high-resolution neutron and synchrotron powder diffraction. In addition, specific heat, magnetization, and dielectric measurements were performed to investigate this phase transition. Although the specific heat and dielectric constant showed anomalies at T S, no transition to a ferroelectric phase was observed in the polarization hysteresis loop down to 30 K. Moreover, a magnetic structure analysis using neutron powder diffraction data revealed a transition from a paramagnetic phase to a G-type antiferromagnetic phase at T N ∼67 K, at which a peak was also observed in the specific heat measurements. The magnetic moments of Co 2+ were aligned along the tetragonal c -axis with a Co 2+ moment of 2.80(1) μ B at 13 K. The rotation and deformation of the CoO2 F4 octahedron due to the large displacement of F atoms were observed at T S from the structural analysis, which play an important role in the structural phase transition in Co3 Sb4 O6 F6 . Highlights: Structural phase transition was observed in oxyfluoride Co3 Sb4 O6 F6 . Antiferromagnetic phase transition was observed at 67 K. Anomaly in the specific heat was observed at approximately 180 K. Structure refinement via high-resolution SPD verified the arrangement of O and F. Displacement of F in CoO2 F4 rotation is important in the structural phase transition.