Dielectric phase transition and symmetry change of constituent molecules in proton-deuteron mixed crystals of squaric acid

Y. Moritomo, Takuro Katsufuji, Y. Tokura

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

We have investigated effects of random substitution of proton sites with deuterons on the temperature- and pressure-induced phase transitions in squaric acid crystal, which consists of ferroelectrically ordered molecular sheets of [C4O4]2- (SQ2-) skeletons and intervening protons or deuterons. In the isotopically mixed crystals (H 1-xDx)2SQ, the critical temperature T c for the dielectric phase transition was found to increase linearly with the deuterium concentration x, while the critical pressure Pc increases nonlinearly with x at 300 K. Around the pressure ∼20 kbar above Pc, the constituent SQ2- skeletons in the paraelectric phase show a symmetry change from the asymmetric (C1h) to centrosymmetric (C4h) form, which is likely caused by the deformation of the correlated proton (deuteron) potential.

Original languageEnglish
Pages (from-to)2244-2251
Number of pages8
JournalThe Journal of chemical physics
Volume95
Issue number4
Publication statusPublished - 1991
Externally publishedYes

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Deuterium
mixed crystals
deuterons
Protons
Phase transitions
musculoskeletal system
Crystals
acids
Molecules
protons
symmetry
molecules
critical pressure
deuterium
critical temperature
substitutes
Substitution reactions
Temperature
crystals
squaric acid

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Dielectric phase transition and symmetry change of constituent molecules in proton-deuteron mixed crystals of squaric acid. / Moritomo, Y.; Katsufuji, Takuro; Tokura, Y.

In: The Journal of chemical physics, Vol. 95, No. 4, 1991, p. 2244-2251.

Research output: Contribution to journalArticle

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