A phenomenological study on ferroelastic KH3(SeO3)2 and KD3(SeO3)2. (November 2021)

• Record Type: Journal Article
• Authors: Kiraci, A.
• Is Part Of: Materials research bulletin. Volume 143(2021)
• Publication Date: 2021-11
• Subjects: Ising model -- Brillouin frequency shift -- critical exponent -- KH3(SeO3)2 -- KD3(SeO3)2; Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2021.111472
• Languages: English
• ISSNs: 0025-5408

Abstract

Highlights: CP and ω of KTS and DKTS have almost the same critical exponent α close to TC . Observed data from the literature are used for calculations. Calculation of the specific heat, the enthalpy and the entropy are carried out. Ising model is adequate to describe the phase transition mechanism in KTS and DKTS. Abstract: The anomalous behavior of the Brillouin frequency shift ω of the soft acoustic mode for KH3 (SeO3 )2 and KD3 (SeO3 )2, and also the volume thermal expansion ∝ V and the specific heat C of KH3 (SeO3 )2 have been analyzed for various temperature intervals close to the phase transition temperatures T C at around 211 K and 302 K, respectively. Our extracted values of the critical exponent from C and ∝ V of KH3 (SeO3 )2 within the temperature intervals of | T − T C | < 7 K are nearly zero, while the critical exponent extracted from the Brillouin frequency shift data of both KH3 (SeO3 )2 and KD3 (SeO3 )2 within the same temperature interval of | T − T C | < 7 K decrease very rapidly toward to zero as the phase transition temperatures are approached. Our results indicate that the critical behavior of ω, ∝ V and C of both KH3 (SeO3 )2 and KD3 (SeO3 )2 can be described with the same critical exponent within the temperature interval of | T − T C | < 2 K . Graphical abstract: Image, graphical abstract