Thermal expansion and a new phase transition in pyroelectric LiKSO4

Sharma, DP (1979) Thermal expansion and a new phase transition in pyroelectric LiKSO4. In: Pramana, 13 (3). pp. 223-230.

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Abstract

Single crystal macroscopic thermal expansion coefficient measurements have been made on uniaxial lithium potassium sulphate crystal both along and normal to the six fold axis, employing Fizeau’s interferometer method. Measurements were made in the range of −120°C to 500°C. The results show that lithium potassium sulphate exhibits two major anomalies in its expansion coefficients around −95°C and 422°C respectively, the one at −95°C has been observed for the first time. The nature of dimensional changes of the crystal at the upper and lower transition points are opposite in nature. The crystal shows considerable lattice anisotropy. Megaw’s tilt concept has been invoked to explain the relative magnitudes of expansion coefficients alonga andc directions. Structural features responsible for the absence of ferroelectricity in this crystal have been pointed out.

Item Type:	Journal Article
Publication:	Pramana
Publisher:	Indian Academy of Sciences
Additional Information:	Copy right of this article belongs to Indian Academy of Sciences.
Keywords:	Thermal expansion - phase transition - ferroelectricity - pyroelectricity
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	07 Jan 2010 04:52
Last Modified:	19 Sep 2010 05:50
URI:	http://eprints.iisc.ac.in/id/eprint/24367

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