Technology and electrophysical properties of multiferroic PZT-PFT ceramics

Abstract

We present the results of obtaining and investigating ceramic samples of solid solution (1-x)(PbZr0:53Ti 0:47O3)-x(PbFe0:5Ta 0:5O3) [i.e. (1-x)PZT-xPFT] with x =0.25, 0.35 and 0.45 obtained using conventional ceramic technology. These materials belong to class of materials known as multiferroics. Solid solutions PZT-PFT are the lowest-loss room-temperature multiferroics known, and as a result there are very interesting for magnetoelectric devices. Paper presents the results of termogravimetric investigations, EDS, XRD and main dielectric measurements. It has been stated that with increasing content of PFT decreases the mean diameter of grains and more wide distribution of grain diameters is observed. For x =0.25 sharp phase transition from ferroelectric phase to paraelectric one is observed and high values of dielectric permittivity. Composition PZT-PFT with x =0.45 has the lowest values of dielectric permittivity, and the transition is more diffused. The increase of x leads also to the shift of the temperature of maximum of dielectric permittivity towards lower temperatures. Samples with x =0.25 and x =0.35 exhibit very low values of dielectric losses up to about 100 C. Dielectric losses for samples with x =0.45 are higher. For obtained PZT-PFT samples we have investigated P–E hysteresis loops at room temperature for frequency 1 Hz. For composition x =0.25 it after application the field about 2.5 kV/mm polarization is equal approximately 28 C/cm2, while for x =0.35, and x =0.45 after application the field about 2.0 kV/mm the polarizations are equal about 25 C/cm2 and 20 C/cm2 respectively. Very low values of losses and high values of polarization lead to the conclusion that interesting material PZT-PFT for applications should be composition with x =0.25.