Change In D-spacing Research Articles

Phase mixing in the critical region of the ferroelectric phase transition in KD 2PO 4

A novel neutron high resolution double crystal arrangement has been used to measure changes in d-spacing, d-spread and mosaicity through the first order ferroelectric phase transition of DKDP. Coexistence of both para and ferroelectric phases was directly observed in the range T c to T c — 3 K. No hysteresis could be detected within the precision of the temperature measurement (10 -3K). The origin of the overshoot effect has been elucidated.