Pressure dependence of the ferroelectric properties of rochelle salt

摘要: The effects of hydrostatic pressure, up to 20 kb (kilobars), on the ferroelectric properties Rochelle salt were investigated. changes in hysteresis loop with increasing pressure at constant temperature resemble closely caused by decreasing atmospheric pressure. At room (19°C), spontaneous polarization, Ps first increases reaches a broad maximum ~ 3.5 and finally decreases zero 10 kb. maximum, has about same value as obtained 5°C thus indicating no large dipole moment electronic ionic contributions total polarization. In vicinity Curie points, P2s is linear function agreement prediction thermodynamic theory. shifts points are close Bancroft's results below kb; however, shift lower point deviates slightly from linearity toward larger slope higher pressures. Above 5 upper occurs above dissociation temperature. paraelectric phases, reciprocal dielectric constant, 1ϵa, is, within small ranges, both discussed terms available theories.