Self-organization of (NH4)2 SO4 and NH4 HSO4 Ferroelectric Domain Structure under Pressure at Phase Transition

Pressure effect on the self-organization of quenched ferroelectric domain structure was studied. A phenomenological model for describing domain ordering has been developed. The nonlinear character of evolution process and the presence of asymmetric polydomain metastable phases was shown. It was established that AHS ferroelectric tends to form polydomain structures at any temperature and pressure values. In AS ferroelectric the formation of both polydomain and single-domain structures was observed. The existence of a critical pressure destroying the ferroelectric phase in AS crystal was established.