scholarly journals Crossover from Ferroelectric to Relaxor Behavior in Ba1−xCaxTiO3 (x = 0.17) System

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2854
Author(s):  
Edita Palaimiene ◽  
Jan Macutkevic ◽  
Juras Banys ◽  
Antoni Winiarski ◽  
Irena Gruszka ◽  
...  
Keyword(s):  
Phase Transition ◽  
Dielectric Properties ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Relaxation Times ◽  
Wide Frequency Range ◽  
Relaxor Behavior ◽  
Arrhenius Law ◽  
Frequency Range ◽  
Ferroelectric Phase Transition Temperature

The dielectric properties of Ba1−xCaxTiO3 (x = 0.17) ceramics were studied in a wide frequency range of 20 Hz–53 GHz. Diffused ferroelectric phase transition was revealed close to 339 K in the dielectric properties of ceramics. The behaviour of distributions of relaxation times in vicinity of the ferroelectric phase transition temperature is also typical for order-disorder ferroelectric phase transition. However, at lower temperatures (below 200 K), the most probable relaxation increased according to the Arrhenius law. At lower temperatures the maximum of the imaginary part of dielectric permittivity versus temperature strongly shifted to higher temperatures when the frequency increased (from 125 K at 1.21 kHz to 300 K at 33 GHz). This behaviour was attributed to the dynamics of Ti ions. The origin of the crossover from ferroelectric to relaxor behaviour of Ba1−xCaxTiO3 (x = 0.17) ceramics is discussed in the paper.

Electrical Properties of Pb(Mg1/3Nb2/3)-PbTiO3 Ferroelectric Single Crystal

2009 ◽  
Vol 421-422 ◽  
pp. 419-422
Author(s):  
Ghulam Shabbir ◽  
Seiji Kojima
Keyword(s):  
Phase Transition ◽  
Electrical Properties ◽  
Single Crystal ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Charge Carriers ◽  
Frequency Range ◽  
Thermally Activated ◽  
Phase Transition Temperatures ◽  
Ferroelectric Single Crystal

The electrical properties of [001]-oriented morphotropic phase boundary (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-33%PT) single crystal have investigated as a function of temperature and frequency. The ac-conductivity exhibited continuous dispersion at all temperatures and frequency range examined and was associated to the thermally activated space charge carriers and local off-centering of Ti4+ and Pb2+ ions. The variations in ferroelectric phase transition temperatures observed in the poled state were associated to the polarization fluctuations and phase co-existence.

Crossover between ferroelectric order and dipolar glass disorder in betaine phosphate0.06betaine phosphite0.94mixed crystals

2015 ◽  
Vol 55 (2) ◽  
Author(s):  
Jūras Banys ◽  
Jan Macutkevic ◽  
Carola Klimm ◽  
Georg Völkel
Keyword(s):  
Phase Transition ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Landau Theory ◽  
Dielectric Strength ◽  
Freezing Temperature ◽  
Wide Frequency Range ◽  
Partial Ordering ◽  
Hydrogen Atoms ◽  
Temperature Dependences

The dielectric properties of mixed betaine phosphate0.06betaine phosphite0.94(BP0.06BPI0.94) ferroelectric crystals were investigated in a wide frequency range from 20 Hz to 3 GHz. Although the dielectric anomaly is clearly observed close to the ferroelectric phase transition temperatureTc= 121 K, the dielectric dispersion is very broad around and below this temperature. Temperature dependences of the dielectric strength, the mean relaxation frequency and the spontaneous polarization cannot be described together according to the Landau theory for ferroelectric phase transition with a single order parameter or according to the quasione-dimensional Ising model. The polarization shows a pronounced distribution in the ferroelectric phase and only a partial ordering of hydrogen atoms occurs down to the lowest temperatures. The unordered hydrogen atoms form a glassy phase and its formation is observed in dielectric spectra at very low temperatures. The proton freezing temperature was estimated.

Sign in / Sign up

Export Citation Format

Share Document