The phase boundary and the domain structure in ferroelastic K2Cd2(SO4)3

In this paper we present results of investigations of the phase boundary dynamic and domain structure in ferroelastic K2Cd2(SO4)(3). The orientation of the phase boundary is determined as (100) and can be explained on the basis of Boulesteix approach and takes into account that the lattice parameters b approximate to c approximate to a(0) at the phase transition point. The phase boundary has diffuse character. The dependence of the phase boundary velocity on the heating and cooling rate is linear. It was found that the "forbidden" domain structure does not appear in thin crystals (d = 0.26 mm); it appears only near the phase boundary in crystals with thickness d = 0.66 mm and exists in a narrow temperature region below T-c in crystals with thickness d = 1 mm. The domain walls in K2Cd2(SO4)(3) cannot be classified as W or W' domain walls.