Premium
Dilatometric and Optical Properties of (CH 3 ) 2 NH 2 Ga(SO 4 ) 2 · 6H 2 O Crystals in Paraelectric and Ferroelectric Phases
Author(s) -
Podsiadła D.,
Czapla Z.,
Andriyevsky B.,
Myshchyshyn O.
Publication year - 2001
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200102)223:3<729::aid-pssb729>3.0.co;2-4
Subject(s) - electrostriction , ferroelectricity , refractive index , dielectric , thermal expansion , uniaxial crystal , anisotropy , condensed matter physics , atmospheric temperature range , polarization (electrochemistry) , crystal (programming language) , phase transition , materials science , chemistry , optical axis , optics , physics , thermodynamics , lens (geology) , optoelectronics , programming language , piezoelectricity , computer science , metallurgy , composite material
Investigations of the temperature dependences of the dimension L i , optical path difference D ij = L i ( n j — 1), and refractive indices n j have been carried out for DMAGaS crystal, (CH 3 ) 2 NH 2 Ga(SO 4 ) 2 · 6H 2 O, in the range of 115–293 K for three principal directions of the optical indicatrix ( i , j = p , m , g ). The minima of the temperature dependences of anisotropy degree indices of the linear thermal expansion A α and refractive indices A n —1 at temperature T c reflect a small disordering of the crystal in the phase transition region. The coefficients of spontaneous linear electrostriction Q L have been found to be almost constant in the temperature range below T c ≈ 136 K. The molecular refraction R , as a parameter of electron polarization due to high frequency light excitation, remains unchanged in the frame of 0.2% in the temperature range of 115–293 K.