ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The main interest in the area of practical applications of ferroelectrics, particularly at the microwave frequency, is oriented now to room temperature. In this connection, ferroelectrics like BaxSr1−xTiO3 should be carefully studied. Such materials are characterized by the second order phase transition. In a perfect ferroelectric crystal, the phase transition takes place at temperature TC, which is called the Curie temperature. Real (defected) crystals and ceramic samples are characterized by a presence of built-in electric field and mechanical strains. In the case of the real crystal, the temperature of the phase transition TC′, is displaced to lower temperature and the temperature of the maximum of cursive-epsilon(T)Tm is displaced to higher value with respect to TC. Thus, for the real ferroelectric sample (not for an incipient ferroelectric), one has TC′〈TC〈Tm. Some investigators suppose by default that TC′=TC=Tm. Such a supposition is wrong and can lead to an incorrect treatment of experimental results. In the case of a thin film sample, the phase transition and the dielectric response of a ferroelectric sample are affected by the size of the sample, what is treated as a size effect. Experimental data obtained as a result of measurement of the dielectric constant as a function of temperature can be used for finding the Curie temperature and other parameters of the material. For this procedure, a suitable model of the dielectric response of the ferroelectric sample should be used. © 2000 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1317243
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