The temperature dependences of the moduli of elasticity cik(T) of single crystals of sodium chlorate NaClO3 and sodium bromate NaBrO3 in the temperature range 77-300 K were investigated experimentally with the help of the resonance method. It is shown that these compounds are elastically anisotropic dielectrics with elastic anisotropy factor A<1 and ratios of the Young moduli and shear moduli of the form E100>E110>E111 and G100<G110<G111. The experimental data on cik(T) were interpreted using a lattice model taking into account the central and noncentral interactions of ions in two coordination spheres. The force constants of these interactions are presented. It is shown that the model chosen describes well the temperature dependences cik(T), if both the noncentral interaction of the ions and the contribution of the vibrational part of the free energy to the moduli of elasticity are taken into account.
ASJC Scopus subject areas
- Physics and Astronomy(all)