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Phase transitions and transport phenomena in Li 0.25 Cu 1.75 Se superionic compound
Author(s) -
Balapanov M. Kh.,
Bikkulova N. N.,
Mukhamedyanov U. Kh.,
Asilguschina G. N.,
Musalimov R. Sh.,
Zeleev M. Kh.
Publication year - 2004
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200402076
Subject(s) - monoclinic crystal system , seebeck coefficient , crystallography , ionic conductivity , lithium (medication) , neutron diffraction , chemistry , phase (matter) , ionic bonding , ion , ionic radius , triclinic crystal system , materials science , thermoelectric effect , crystal structure , thermodynamics , electrolyte , medicine , physics , endocrinology , organic chemistry , electrode
Phase transformation points in Li 0.25 Cu 1.75 Se mixed electronic–ionic conductor have been determined by calorimetric, conductometric and thermoelectric measurements. The phase transformation (PT) from triclinic to monoclinic occurs at 403–413 K. At 503–515 K the monoclinic phase is followed by a rhombohedral modification. Both of these PTs are accompanied by drops on the calorimetric curve. At about 653 K observed anomalies in the temperature dependencies of the ionic conductivity, of the chemical diffusion coefficient and the jump of the ionic Seebeck coefficient have been induced by the PT to hexagonal phase. Neutron diffraction studies reveal the cubic structure of Li 0.25 Cu 1.75 Se compound (with space group Fm3m) at 773 K. The corresponding PT causes anomalies in the electrical and diffusion properties at 703–713 K. Cu ions are statistically distributed over tetrahedral and trigonal voids in an Fm3m cage; lithium ions randomly occupy 32(f) positions. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)