R. Tchukvinskyi et al., DIELECTRIC STUDY OF THE FERROELECTRIC PHASE-TRANSITION IN DMAGAS CRYSTAL, Zeitschrift fur Naturforschung. A, A journal of physical sciences, 53(3-4), 1998, pp. 105-111
Electric permittivity measurments as functions of temperature at const
ant de electric field and as functions of the de electric field at con
stant temperatures in the paraelectric phase have been performed for D
MAGaS crystal. The changes of the permittivity maximum with the electr
ic field intensity evidence the first-order character of the ferroelec
tric phase transition at T-cl The field dependence of the permittivity
epsilon(E) in the paraelectric phase is discussed, using the classica
l electric equation of state. A method for the determination of the co
rresponding coefficients is proposed. The obtained B and C coefficient
s, together with double hysteresis loop observed above T-cl prove the
first-order character of the ferroelectric phase transition in DMAGaS
crystal.