Effects of the lapped surface layers on the dielectric properties of ferroelectric ceramics

Abstract

The effects of lapped surface layers on the dielectric properties of Ba- and Sr-modified lead titanate and lead zirconate ferroelectric ceramics are examined. Specimens with lapped surfaces show anomalous dielectric behaviors, namely, smaller dielectric constant, higher Curie temperature, smaller dielectric loss (below Curie point), and smaller remanent polarization than those of specimens whose surface layers are removed by chemical etching. This may be ascribed to the existence of a lapped surface layer, which seems to be a (0.1–2)-μm-thick nonferroelectric layer of small dielectric constant with a two-dimensional tensile stress of 5–15 kbars. The thinness of the layer results in a large capacitance on the order of 0.5 μF/cm2. The above model for lapped surface layer, especially involving the two-dimensional tensile stress, explains well the anomalous dielectric behaviors measured in this paper.

Thickness‐Dependent Properties of Relaxor‐PbTiO3 Ferroelectrics for Ultrasonic Transducers

“…Subbarao et al16 measured surface polarization using thermal and acoustic pulse measurements, revealing a decrease in polarization in the regions closest to the surface compared to the overall polarization. Jyomura et al17 studied the influence of lapped surfaces on the dielectric properties, and found that the samples prepared by lapping exhibited a lower dielectric permittivity and remnant polarization, compared to the samples prepared by chemical etching. Furthermore, using X‐ray diffraction, Cheng et al18 and Mehta et al19 observed domain reorientation in surface regions well beyond that achieved by the electric field when the sample surfaces were finished with grinding and/or polishing by 45‐μm diamond.…”

Scaling effects of relaxor-PbTiO3 crystals and composites for high frequency ultrasound

“…16,17 A series capacitance model, in which damage layers exist in series with the normal ferroelectric portion, has been used to explain the degraded dielectric permittivity as function of the thickness of the nonferroelectric layers/samples. 18 Property degradation in ferroelectric materials may also be associated with their respective domain sizes. It is well known that the dielectric and piezoelectric response of ͓001͔poled relaxor-PT single crystals is related to the engineered domain configuration and polarization rotation mechanism.…”

A Two-Step Annealing Method to Enhance the Pyroelectric Properties of Mn:PIMNT Chips for Infrared Detectors

“…From Figure 7, with the Figure 7 displays the dielectric properties (ε r and tanδ measured at 1 kHz after poling) and pyroelectric properties (p, F i , F v and F d ) of the thin Mn:PIMNT pyroelectric chips annealed at different temperatures. Note that the electrical properties of the thin Mn:PIMNT pyroelectric chips are slightly different from those of the thick Mn:PIMNT crystals, which is related to the size effect and the surface effect [42][43][44][45][46][47]. The slightly higher pyroelectric coefficient of the thin Mn:PIMNT pyroelectric chips can be attributed to the measurement characteristic of the dynamic method, which measures the temperature change of the samples by measuring that of the sample stage.…”

“…For the thick Mn:PIMNT crystals, the actual temperature change is lower than the measured temperature change due to the thickness, meaning that the obtained pyroelectric coefficient is relatively lower than the actual value. The slightly lower εr and higher tanδ are the result of the interaction of the surface damage layer and surface stress, which can be ignored in thick Mn:PIMNT crystals [43,45]. From Figure 7, with the Figure 7 displays the dielectric properties (ε r and tanδ measured at 1 kHz after poling) and pyroelectric properties (p, F i , F v and F d ) of the thin Mn:PIMNT pyroelectric chips annealed at different temperatures.…”