The phase front coexistence in DKDP crystal in the field of small temperature gradient

The results show that for a small temperature gradient G similar to 10(-2) K/mm perpendicular to the ferroelectric c axis there is observed only one quasiplanar phase front, slightly inclined to the plane perpendicular to the c-axis which crosses the crystal laterally in this direction. The angle beta between this phase front and the (001) plane in a perfect crystal never exceeds the critical angle beta*similar to 22 degrees of are. Vice-versa when the phase front is caught by the tilted planar defect, the phase front may fit its form with superior angle.