Structural phase transitions in layered perovskitelike crystals

Journal Article · Wed Mar 01 00:00:00 EST 1995 · Crystallography Reports

OSTI ID:255067

Aleksandrov, K S ^[1]

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1. Krasnoyarsk State Univ. (Russian Federation)

Possible symmetry changes due to small tilts of octahedra are considered for layered perovskite-like crystals containing slabs of several ({ell}) layers of comer-sharing octahedra. In the crystals with {ell} > 1, four types of distortions are possible; as a rule, these distortions correspond to the librational modes of the parent lattice. Condensation of these soft modes is the reason for structural phase transitions or sequences of phase transitions. The results obtained are compared with the known experimental data for a number of layered ferroelectric and ferroelastic perovskite-like compounds. An application of the results to the initial stage of determining unknown structures is discussed with particular attention paid to high-temperature superconductors. 76 refs., 9 figs., 7 tabs.

• OSTI ID: 255067
• Journal Information: Crystallography Reports, Vol. 40, Issue 2; Other Information: PBD: Mar-Apr 1995; TN: Translated from Kristallografiya; 40: No. 2,279-301(1995)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
PEROVSKITES
PHASE TRANSFORMATIONS
CRYSTALS
CRYSTAL STRUCTURE
HIGH-TC SUPERCONDUCTORS
SYMMETRY
ORDER PARAMETERS