The Dielectric Studies of Ferroelectric [NH2(CH3)2]3Sb2Cl9 Crystals under Moderate Pressure
M. Zdanowska-Frączeka, M. Olszewskia, Z.J. Frączeka and R. Jakubasb
aInstitute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland
bFaculty of Chemistry, Wrocław University, Joliot-Curie 14, 50-385 Wrocław, Poland
Full Text PDF
Received: 24 08 2007; Revised version: 20 09 2007;
The effect of pressure on the dielectric properties of [NH2(CH3)2]3Sb2Cl9 crystal was analyzed for a few values of hydrostatic pressure within the range from 0.1 MPa to 300 MPa and for temperatures from the range of 220-350 K. The measuring frequency was 1 kHz. The pressure-temperature phase diagram obtained was nonlinear. The temperature dielectric permittivity anomalies related to the paraelectric-ferroelectric phase transition temperature (Tc) gradually increase up to 66 MPa and then decrease with subsequent increase in pressure. The character of the temperature dielectric permittivity anomalies, typical of the continuous ferroelectric transition, remains unchanged with increasing pressure. Additionally, the pressure dependences of the Curie-Weiss constants for the crystal in paraelectric (C+) and ferroelectric (C-) phases were evaluated and discussed. The results indicated a complex mechanism of the ferroelectric phase transition.
DOI: 10.12693/APhysPolA.112.549
PACS numbers: 71.45.Gm, 77.84.Fa, 77.22.Ch, 77.80.Bh