The influence of the relative thermal expansion and electric permittivity on phase transitions in the perovskite-type bidimensional layered NH3(CH2)3NH3CdBr4 compound. (July 2017)

• Record Type: Journal Article
• Authors: Staśkiewicz, Beata; Staśkiewicz, Anna
• Is Part Of: Journal of physics and chemistry of solids. Volume 106(2017)
• Page Start: 65
• Page End: 75
• Publication Date: 2017-07
• Subjects: Organic compounds -- Inorganic compounds -- Phase transitions -- Thermal expansion -- Electrical properties; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2017.03.007
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: Hydrothermal method has been used to synthesized the layered hybrid compound NH3 (CH2 )3 NH3 CdBr4 of perovskite architecture. Structural, dielectric and dilatometric properties of the compound have been analyzed. Negative thermal expansion (NTE) effect in the direction perpendicular to the perovskite plane as well as an unusual phase sequence have been reported based on X-ray diffraction analysis. Electric permittivity measurements evidenced the phase transitions at T c 1 =326/328 K and T c 2 =368/369 K. Relative linear expansion measurements almost confirmed these temperatures of phase transitions. Anomalies of electric permittivity and expansion behavior connected with the phase transitions are detected at practically the same temperatures as those observed earlier in differential scanning calorimetry (DSC), infrared (IR), far infrared (FIR) and Raman spectroscopy studies. Mechanism of the phase transitions is explained. Relative linear expansion study was prototype to estimate critical exponent value β for continuous phase transition at T c 1 . It has been inferred that there is a strong interplay between the distortion of the inorganic network, those hydrogen bonds and the intermolecular interactions of the organic component. Highlights: Phase transitions in layered compound have been studied by different measurements. The two phase transition was evident. Negative thermal expansion effect and an unusual phase sequence have been reported. Critical exponent value for continuous phase transition was estimated.