Effect of nonstoichiometry on the dielectric permittivity of TlInS2 near phase transitions

• Published in: Inorganic materials Vol. 39; no. 4; pp. 327 - 329
• Main Authors: SARDARLY, R. M, SAMEDOV, O. A, SADYKHOV, I. Sh, NADZHAFOV, A. I, EYUBOVA, N. A, MAMEDOV, T. S
• Format: Journal Article
• Language: English
• Published: New York, NY Springer 01-04-2003
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Permittivity (dielectric function); Physics; DTA; Temperature dependence; Stoichiometry; Monocrystals; Inorganic compounds; Ferroelectric materials; Phase transformations; Ternary compounds; Thallium sulfides; Experimental study; Permittivity; Indium sulfides
• ISSN: 0020-1685; 1608-3172
• DOI: 10.1023/A:1023207211502

According to neutron and xrd studies, the monoclinic structure of the layered ferroelectric TlInS2 undergoes consecutive phase transitions to a commensurate polar phase with a polarization vector lying in the basal plane and to an intermediate, incommensurate phase. It was pointed out in a number of studies that the temperature variation of dielectric permittivity for TlInS2 depended on the preparation procedure. To clarify the origin of the non-reproducibility of the data, we measured the permittivity of several TlInS2 single crystals. Temperature-dependent dielectric permittivity measurements and differential thermal analysis demonstrate that even slight deviations from stoichiometry have a significant effect on the dielectric properties of ferroelectric TlInS2 crystals.