This article is cited in 2 papers

CONDENSED MATTER

Fluctuations and Landau—Devonshire expansion for barium titanate

A. I. Sokolov^a, A. K. Tagantsev<sup>b

a</sup> St. Petersburg Electrotechnical University, St. Petersburg, Russia
^b École Polytechnique Fédérale de Lausanne

Abstract: The experimentally observed temperature dependence of the quartic coefficients in the Landau—Devonshire expansion for BaTiO$_3$ is naturally accounted for within a proper fluctuation model. It is explained, in particular, why one of the quartic coefficients varies with temperature above $T_c$ while the second is constant. The tetragonal phase in BaTiO$_3$ is argued to exist essentially due to the thermal fluctuations, while the true Landau—Devonshire expansion with temperature-independent coefficients favours the rhombohedral ferroelectric phase.

PACS: 77.80.Bh, 77.84.Bw

Received: 21.02.2002
Revised: 18.03.2002

Language: English

 English version: Journal of Experimental and Theoretical Physics Letters, 2002, 75:8, 410–414

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