Temperature Dependence of Energy Storage Density and Differential Permittivity and Bandgap Study of Relaxor (Pb,La)Zr0.65Ti0.35O3
TL;DR: In this paper, the diffusivity values of Pb(1-3x/2)LaxZr0.65Ti0.35O3 (x = 6, 7, 8, 8 and 9%) were obtained.
Abstract: Pb(1-3x/2)LaxZr0.65Ti0.35O3 (x = 6, 7, 8 and 9%) show diffusivity values as 1.55, 1.72, 1.94 and 2.18, respectively. The differential permittivity strongly depends on temperature and electric field...
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TL;DR: In this paper, an ultrahigh energy storage density (W) was achieved in the Ba0.3Sr0.7Zr 0.18Ti0.82O3 (BSZT) relaxor ferroelectric thin films with the help of an ultrathin Ca0.8O1.8 (CSZ) artificial dead layer.
33 citations
TL;DR: In this article, a high-energy ball-milling technique was used to synthesize (Pb0.92La0.08) (Zr0.60Ti0.40) O3 (PLZT 8/60/40) ceramics for microwave sintering at different temperatures from 900 °C to 1200 °C.
Abstract: In this study, (Pb0.92La0.08) (Zr0.60Ti0.40) O3 (PLZT 8/60/40) ceramics were synthesized using a high-energy ball-milling technique followed by microwave sintering at different temperatures from 900 °C to 1200 °C. The optimal microwave sintering temperature for the PLZT 8/60/40 ceramics was found to be 1150 °C, which is relatively low compared with conventional sintering temperature. The sintered ceramics show the pure perovskite phase, uniform grain microstructure (1.2 µm) and high density (~99.5%). The polarization vs. electric field (P-E) hysteresis curves were used to investigate the ferroelectric and energy storage properties. The switching characteristic in P-E loops and occurrence of domain switching current in current vs. electric field (I-E) loops confirms their ferroelectric nature. The PLZT ceramics, which were sintered at 1150 °C, show the highest remnant polarization (Pr) of ~32.18 μC/cm2 and domain switching current (Imax) of ~0.91 mA with a low coercive field (Ec) of ~10.17 kV/cm. The bipolar and unipolar strain vs. electric field (S-E) hysteresis loops were also measured and the highest unipolar strain was found to be ~0.26% for the PLZT ceramics sintered at 1150 °C. The unipolar S-E curves were used to derive the piezoelectric coefficient (d33~495 pm/V) and a strain hysteresis loss (~5.8%).
5 citations
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01 Jan 1973
TL;DR: In this paper, the dielectric, hysteresis, and optical properties of quasi-ferroelectric PLZT ceramics have been investigated for the representative 9/65/35 composition which was prepared as a transparent ceramic by means of a two-stage sintering-densification process.
Abstract: Certain compositions within the quaternary lead-lanthanum-titanate-zirconate (PLZT) system exhibit neither a "true" ferroelectric nor a "true" paraelectric behavior and are therefore best characterized as quasi-ferroelectric. The dielectric, hysteresis, and optical properties of quasi-ferroelectric PLZT ceramics have been investigated for the representative 9/65/35 composition which was prepared as a transparent ceramic by means of a two-stage sintering-densification process. The results of these studies suggest that the quasi-ferroelectric behavior of PLZT compositions between their Curie temperature and a transition temperature T p is brought about by the existence of polar distorted microregions (polar short-range order). By applying an electric field a transition to a macroscopic ferroelectric (FE) state (polar long-range order) is enforced which is, however, not stable at zero field at T > T p . This concept, which explains the experimental observations, is compared with the possibility of a FE to anti-FE phase transition at T p . Attention is drawn to the quasi-static memory behavior of this type of material that can be realized by disconnecting the sample in its ON state from the voltage source and which might enlarge the scope of applications of quasi-ferroelectric PLZT ceramics.
77 citations
TL;DR: In this article, the authors measured the full hysteresis loops for the relaxor ferroelectric 8/65/35 PLZT as a function of temperature and showed a quadratic relationship below the Curie peak with a nearly temperature-independent electrostrictive coefficient.
70 citations
01 Jan 1973
TL;DR: In this paper, the properties of lead zirconate titanate-titanate (PLZT) ceramics were investigated and it was shown that the phase equilibria in 65/35 PLZT depend strongly on the state of polarization.
Abstract: The interaction of structure with optical and electrical properties in lanthanum-doped lead zirconate-titanate (PLZT) ceramics is complex. An interpretation is presented which shows the critical dependence of structure and, hence, properties on the state of polarization, the temperature, and the La content. To explain the behavior of PLZT ceramics two new concepts are presented: polymorphism and penferroelectricity. Polymorphism occurs when either electrical or mechanical ordering fields generate a hybrid crystal structure in which an individual grain attains a crystal structure dependent on its orientation with respect to the field. Penferro-electricity refers to the condition in which material is noncubic and polar but with such a low spontaneous polarization that no domains exist. The justification for applying these concepts to PLZT rests on the existing structural, optical, and dielectric data supplemented by new X-ray evidence and new data on the temperature dependence of optical and electrical properties. Emphasis is placed on materials with 65/35 Zr/Ti ratio and 6 < X ≤ 8 where X is the atom % La substituted for Pb. Analysis of existing data disclosed 1) a lack of X-ray evidence for the morphotropic boundary predicted by average remanent birefrigence and planar coupling and 2) a discrepancy in the position of the phase transition located by the Curie point and by planar coupling coefficient. The new X-ray, optical insertion loss, dielectric and piezo-electric data show conclusively that the phase equilibria in 65/35 PLZT depend strongly on the state of polarization. In thermally annealed ceramics a state of penferroelectricity exists between the cubic paraelectric state and the rhombohedral ferroelectric state. Rhombohedral ferroelectric material with 6 < X < 8 transforms to polymorphic material with very strong ferroelectric properties during poling. Because of the large crystal distortions which accompany poling, the optical transmission in the poled state is much reduced. This behavior is the basis for many of the useful device applications of PLZT in this compositional range.
62 citations
TL;DR: In this article, the results of dielectric and pyroelectric investigations of the diffuse phase transition in PLZT X/65/35 X = 7,8,9,10 ceramics were presented.
Abstract: The paper presents the results of dielectric and pyroelectric investigations of the diffuse phase transition in PLZT X/65/35 X = 7,8,9,10 ceramics. In the dielectric study the measuring frequency was varied between 1 kHz and 2 MHz. The results of the dielectric study are interpreted according to the relaxor theory of diffuse phase transitions (DPT).
57 citations
TL;DR: A relaxor-ferroelectric phase transition takes place in PLZT (6-7)/65/35 at temperature lower than the temperature of the dispersive dielectric constant maximum.
Abstract: Dielectric and light scattering measurements are performed in lanthanum modified lead zirconate titanate (PLZT) (6–8)/65/35 hot-pressed ceramics in order to refine the phase diagram. A relaxor-ferroelectric phase transition takes place in PLZT (6–7)/65/35 at temperature lower than the temperature of the dispersive dielectric constant maximum. At this temperature the size of polar regions "a" essentially increases up to a>λ (=0.63 µ m). The appearence of ferroelectric long-range order in PLZT with decreased concentration of La ions is explained by larger coupling between ferroelectrically active BO6 octahedrons due to the smaller concentration of defects and higher dielectric constant.
54 citations