The processing, electromechanical properties, and microstructure of lead zirconate titanate (PZT) ceramics over the grain-size range of 0.1-10 μm were studied. Using measurements over a large temperature range (15-600 K), the relative role of extrinsic contribution (i.e., domain-wall motion) was deduced to be influenced strongly by the grain size, particularly for donor-doped PZT. Analytical transmission electron microscopy studies were conducted to investigate the trend in domain configurations with the reduction of grain size. The correlations between domain density, domain variants, domain configurations (before and after poling), spontaneous deformation, and the elastodielectric properties were qualitatively discussed, leading to new insights into the intrinsic and extrinsic effects and relevant size effects in ferroelectric polycrystalline materials.

Intrinsic and Extrinsic Size Effects in Fine-Grained Morphotropic-Phase-Boundary Lead Zirconate Titanate Ceramics

During the last few years ferroelectric ceramics have attained increasing importance as materials for electronic devices. Present world production of such devices is more than 1010 per year. Since the suitability of these materials is due to their ferroelectric nature, this paper will mainly discuss the correlation of their physical ferroelectric behaviour and their many applications.As compared to single crystalline materials, polycrystalline ceramics are preferred firstly because of their lower cost and secondly because of the possibility of preparing doped mixed crystals of almost any composition with optimum properties. On the other hand certain disadvantages are present in ceramics: the physical effects in single crystals can only partially be exploited in ceramics. Furthermore ceramics suffer from characteristic instabilities.The materials discussed here are all oxides based on BaTiO3 and Pb(Ti, Zr)O3 with perovskite structure. The large variation of their physical properties, which is very convenie...

Physics of ferroelectric ceramics used in electronic devices

Dielectric, ferroelectric and electric field-induced strain properties of (Pb1-xBax)(Zr1-yTiy)O3 ceramics with 0.15 ≤ x ≤ 0.45 and 0.16 ≤ y ≥ 0.70 were investigated. A wide range of compositions possessing relaxor phase characteristics was found to exist near the boundaries between the ferroelectric rhombohedral, tetragonal and paraelectric cubic phases. Within this compositional range, broadened peaks of dielectric constant as a function of both composition and temperature were identified as well as slim loop hysteresis and frequency-dependent relaxation behavior. Longitudinal field-induced strain for some selected samples and transverse strain for all the compositions studied were determined. Maximum total and differential strains were found in the vicinity of the rhombohedral-tetragonal phase boundary. Optimal values of the differential strain were close to (about 80%) those found in PLZT ceramics. Inside the relaxor phase region the relationship between the strain and electric field (or polar...

Dielectric, ferroelectric and electric field-induced strain properties of (Pb1-xBax)(Zr1-yTiy)O3 ceramics

Phase transitions in $BaTiO_3$ doped with neodymium have been studied using temperaturecapacitance measurements, differential scanning calorimetry, X-ray powder diffraction and electron paramagnetic resonance spectroscopy. The coexistence of a para-electric cubic phase with the ferroelectric tetragonal and orthorhombic phases is noticed within the temperature range corresponding to the stability region of the latter phases in undoped $BaTiO_3$. The broad maximum in the effective dielectric constant shifts to lower temperature with increase in neodymium content. The heat of transformation measured at the Curie point tends to zero above 3.5 at% Nd and the phase transition gradually approaches the second order. These are characteristics of a diffuse phase transformation. Using the quantitative results from the above studies, a T-x topological diagram is constructed for the $BaTiO_3-xNd$ system where x < 5.5at%. The phase contents vary with processing parameters as well as grain size, and the very existence of more than one phase in a given area of the T-x diagram indicates the metastable thermodynamic equilibrium prevailing in $BaTiO_3$-Nd ceramics. The inhomogeneous distribution of lattice defects may be the major cause for such a behaviour.

Diffuse phase transformations in neodymium-doped BaTiO3 ceramics

https://ris.utwente.nl/ws/files/6881566/Keizer78anomalous.pdf

Anomalous dielectric behaviour of La(III) substituted lead titanate ceramics

https://ris.utwente.nl/ws/files/6486174/burggraaf75effects.pdf

A.J. Burggraaf

Papers

Effects of microstructure on the dielectric properties of lanthana substituted PbTiO3 and Pb (Zr, Ti) O3-ceramics