A new Kosters prism interferometer for simultaneous determination of refractive index and thermal expansion of crystals as a function of temperature
UNSPECIFIED (1996) A new Kosters prism interferometer for simultaneous determination of refractive index and thermal expansion of crystals as a function of temperature. JOURNAL OF APPLIED CRYSTALLOGRAPHY, 29 (Part 5). pp. 574-583. ISSN 0021-8898Full text not available from this repository.
An uniquely-modified Kosters prism interferometer for the simultaneous and independent measurement of refractive index, delta n(T), and thermal expansion, delta l(T), as a function of temperature in the range 308-1273 K, is described. The capabilities of the system are demonstrated via measurement of delta n(T) and delta l(T) along both the  and  directions up to and through the alpha-beta phase transition in quartz, with results in good agreement with previous measurements. Further to this, experiments to determine delta n(T) and delta l(T) along the ,  and  directions in the orthorhombic nonlinear optical crystal indium-doped KTiOAsO4 are described. The results are used to show that the ferroelectric-paralectric phase transition at T-c = 1063 K is second-order and exhibits Landau-type behaviour over a range of 100 K below T-c. Finally, similar experiments on the orthorhombic crystal Ba2NaNb5O15 are reported. The behaviours of delta n(T) and delta l(T) at the ferroelastic phase transition at 563 K and the ferroelectric-paraelectric phase transition at T-c = 849 K are discussed. Clear evidence of the existence of polar fluctuations in the paraelectric phase is presented.
|Item Type:||Journal Article|
|Subjects:||Q Science > QD Chemistry|
|Journal or Publication Title:||JOURNAL OF APPLIED CRYSTALLOGRAPHY|
|Publisher:||MUNKSGAARD INT PUBL LTD|
|Date:||1 October 1996|
|Number of Pages:||10|
|Page Range:||pp. 574-583|
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