Heat capacity and magnetic properties of fluoride CsFe2+Fe3+F6 with defect pyrochlore structure

Mikhail V. Gorev (1, 2) , Igor N. Flerov (1, 2) , Alain Tressaud (3) , Evgeny V. Bogdanov (1, 4) , Andrey V. Kartashev (1, 5) , Oleg A. Bayukov (1) , Evgeny V. Eremin (1, 2) , Alexander S. Krylov (1)

1 L.V. Kirensky Institute of Physics
2 Institute of Engineering Physics and Radio Electronics
3 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
4 Astafijev Krasnoyarsk State Pedagogical University
5 Krasnoyarsk State Agrarian University

Heat capacity, Mössbauer and Raman spectra as well as magnetic properties of fluoride CsFe2F6 with defect pyrochlore structure were studied. In addition to recently found above room temperature three successive structural transformations Pnma-Imma-I41amd-Fd-3m, phase transition of antiferromagnetic nature with the 13.7 K Neel temperature and a broad heat capacity anomaly with a maximum at about 30 K were observed. The room temperature symmetry Pnma is unchanged at least down to 7 K. Simple model of indirect bond used to estimate the exchange interactions and to propose a magnetic structure model.

Mots clés: Pyrochlore structure; Phase transition; Magnetic properties; Thermal properties

Domaines: Matériaux

Mikhail V. Gorev, Igor N. Flerov, Alain Tressaud, Evgeny V. Bogdanov, Andrey V. Kartashev, et al.. Heat capacity and magnetic properties of fluoride CsFe2+Fe3+F6 with defect pyrochlore structure. Journal of Solid State Chemistry, 2016, 237, pp.330-335. ⟨10.1016/j.jssc.2016.02.045⟩. ⟨hal-01287796⟩