Abstract
High resolution synchrotron radiation X-ray powder diffraction was used to investigate the melting of the cooperative Jahn-Teller distortion (cJTd) in a perovskite of composition KCu0.8Mg0.2F3. A first order phase transition relaxing the cJTd is observed at T ∼ 600 K. From the transition temperature, an estimation of kT is derived (kT = 0.05 eV) for the cJTd in the doped compound. This is the very first observation of cJTd melting in a compound of the series KCu1−x Mg x F3. A structural phase diagram for the Cu rich zone of the series is proposed. In principle, the extension of this experimental investigation could be used to disentangle the orbital order (OO) and cJTd energy scales in the parent compound KCuF3, a test system for OO theories.
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References
K.I. Kugel, D.I. Khomskii, Sov. Phys. Usp. 25, 231 (1982)
T. Hotta, S. Yunoki, M. Mayr, E. Dagotto, Phys. Rev. B 60 (1999), R15009, and references therein
R. Caciuffo, L. Paolasini, A. Sollier, P. Ghigna, E. Pavarini, J. van den Brink, M. Altarelli Phys. Rev. B 65, 174425 (2002)
R.H. Buttner, E.N. Maslen, N. Spadaccini, Acta Cryst. B 46, 131 (1990)
S.K. Satija, J.D. Axe, G. Shirane, H. Yoshizawa, K. Kirakawa, Phys. Rev. B 21, 2001 (1980)
C. Oliva, M. Scavini, S. Cappelli, C. Bottalo, C. Mazzoli, P. Ghigna, J. Phys. Chem. B 111, 5976 (2007)
A.N. Fitch, J. Res. Natl. Inst. Stand. Technol. 109, 133 (2004)
A.C. Larson, R.B. Von Dreele, General Structure Analysis System (GSAS) (Los Alamos National Laboratory Report LAUR, 2004), pp. 86–748
B.H. Toby, J. Appl. Cryst. 34, 210 (2001)
T. Tanaka, M. Matsumoto, S. Ishihara, Phys. Rev. Lett. 95, 267204 (2005)
S. Ishihara, T. Tanaka, M. Matsumoto, J. Mol. Struct. 838, 216 (2007) and references therein
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Scavini, M., Brunelli, M., Ferrero, C. et al. Experimental estimation of the cooperative Jahn-Teller energy in orbitally ordered KCu0.8Mg0.2F3 perovskite. Eur. Phys. J. B 65, 187–190 (2008). https://doi.org/10.1140/epjb/e2008-00338-y
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DOI: https://doi.org/10.1140/epjb/e2008-00338-y