PLZST Antiferroelectric Ceramics Research Articles

Preparation of PLZST antiferroelectric ceramics by hydroxide coprecipitation method

Abstract An improved coprecipitation method using buffer solution was developed for synthesizing Pb 0.97 La 0.02 (Zr 0.75 Ti 0.08 Sn 0.17 )O 3 antiferroelectric ceramics. It was found that the perovskite phase was formed when the precursor powders were calcined at 550 °C for 2 h and the average diameter of these particles was less than 100 nm. Moreover, the results showed that when the pH value of the precipitating solution was in the range of 8.9–9.0, in comparison with the ceramics prepared by conventional solid state reaction, the samples synthesized by coprecipitation method had a larger electric field-induced phase transition and higher breakdown strength, which lay a basis for preparing high power energy storage capacitors and pulsed power applications.

Effect of Glass Additive on Electrical Properties of PLZST Antiferroelectric Ceramics

Alkali-free barium boroaluminosilicate glass-modified PLZST antiferroelectric ceramics with glass contents between 0 and 8 wt.% have been fabricated respectively by a traditional solid phase reaction. The PLZST ceramics doped with alkali-free barium boroaluminosilicate glass showed typical antiferroelectric phase when the glass contents were below 6 wt.% and the refined grains were observed. The addition of glass decreased the dielectric constant of samples. With increasing of the glass additives, both the Curie temperature and the remanent polarization deceased. It may be that Ba2+entered in the perovskite structure, which acts as an important modified ion in the alkali-free barium boroaluminosilicate glass. Larger forward antiferroelectric-ferroelectric phase transition field (EAFE-FE>50 kV/cm) and higher breakdown strength (EBDS≥105 kV/cm) were displayed in glass-modified PLZST ceramics. The improvement properties of samples were benefit for energy storage which is desired for the high power energy storage capacitors and pulsed power applications.

Effect of Sn:Ti variations on electric filed induced AFE–FE phase transition in PLZST antiferroelectric ceramics

The effect of Sn:Ti variations on antiferroelectric to ferroelectric phase transition of (Pb 0.97La 0.02)(Zr 0.65Sn 0.35− x Ti x )O 3 ( x = 0.08–0.11) ceramics with compositions near antiferroelectric to ferroelectric morphotropic phase boundary was studied. X-ray diffraction showed that all samples were tetragonal phase at room temperature. With the increase of x from 0.08 to 0.1, all samples showed the typical antiferroelectric double loops. The critical value E AF of the electric-field induced antiferroelectric to ferroelectric phase transition decreased from 64 kV/cm to 38 kV/cm, and the electric field E FA of induced-ferroelectric to antiferroelectric phase transition decreased from 44 kV/cm to 10 kV/cm. A high polarization of the sample with x = 0.1 can be induced with a lower electric filed. The variations of Sn:Ti ratio had no effect on hysteresis of Δ E (= E AF − E FA), but Δ E reduced with temperature increasing. The virgin sample of which x = 0.11 was intrinsic antiferroelectric phase, but the remanent polarization of induced-ferroelectric phase remained after electric-field was removed at room temperature.

The role of front electrode in electron emission from ferroelectric cathode

Electron emission from ferroelectric cathode (FEE) is unconventional electron emission effect. Experimental studies on ferroelectric emission (properties of PLZST antiferroelectric ceramics samples) at room temperature and in low vacuum had been carried out. Both islands electrode and stripes electrode were used in experiments. The influences of front electrode patterns on electron emission were investigated by measuring the emission current from the sample. It had been found that different patterned front electrodes yielded different emission current. The islands electrode emitted lower current than the stripes electrode.

Effect of Ti4+:Sn4+ ratio on the phase transition and electric properties of PLZST antiferroelectric ceramics

PLZST antiferroelectric ceramics were synthesized by the modified coprecipitation method. Effect of variations in the Ti4+:Sn4+ ratio on phase and properties were evaluated. The XRD patterns show that with the increasing of Ti4+ content, the structure of ceramics changes from tetragonal phase to rhombohedral phase and this was certified by the P–E hysteresis loops. The temperature dependence of dielectric constant of the ceramics was measured. Low frequency dispersion at room temperature disappeared when the temperature increased and the variation of Tm is not linear with the content of Ti4+. These unusual behaviors had been interpreted.

Phenomenon of multiple field-induced phase transition in PLZST antiferroelectric ceramics

The multiple field-induced phase transition in 4 at. % La modified Pb(Zr, Sn, Ti) O3 family with temperature from-40°C to 46°C in reported. Two electric field-indud transitions from a metastable antiferroelectric phase to two ferroelectric phases are observed is polarization at the applied field of 4 MV/m. The critical field of phaae transition between two ferroelectric phases is not larger than 2.5 MV/m, about ten to twenty percent of that ever found in PZT bawd ceramics. Lattice structure is shown to be orthorhombic by X-ray diffraction. Dielectric investigation reveals a relaxor-like ferroelectric behavior. Temperatureeltrtric field phase diagram is also presented. An appreciate kind of materials is provided to investigate multiple field-induced phase transition with I’ZT-bRd ceramics.