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Ceramic‐based dielectric capacitor are highly suitable for pulsed power applications due to their high power density and excellent reliability. However, the ultrahigh applied electric field limit their applications in integrated electronic devices. In this work, (1−x){0.96(Bi0.5Na0.5)(Ti0.995Mn0.005)O3‐0.04BiAlO3}‐xNaNbO3 (BNT‐BA‐xNN, x = 0, 0.04, 0.08, 0.12, and 0.16) ternary ceramics were designed to achieve excellent energy storage properties. It was found that the introduction of NaNbO3 (NN) effectively increase the difference (ΔP) between Pmax and Pr, resulting in an obvious enhancement of the energy storage properties. High recoverable energy storage density, responsivity, and power density, that is, Wrec = 2.01 J/cm3, ξ = Wrec/E = 130.69 J/(kV⋅m2), and PD = 25.59 MW/cm3, accompanied with superior temperature stability were realized at x = 0.14 composition. In addition, the thermal stable dielectric properties of the sample can be prominently improved with increasing NN content. The temperature coefficient of capacitance (TCC) of x = 0.16 composition is lower than 15% over the temperature range from 49°C to 340°C, with a high dielectric permittivity of 1647 and a low dielectric loss (0.0107) at 150°C. All these features show that the BNT‐BA‐xNN ceramics are promising materials for energy storage application. [ABSTRACT FROM AUTHOR]

Dynamic temperature sensing and infrared detection/imaging near room temperature are critical in many applications including invasive safety alarming, energy conversion, and public health, in which ferroelectric (FE) materials play an extremely important role due to their pyroelectricity. As a result, over the past few decades many efforts have been made to improve the understanding of pyroelectrics, explore new pyroelectric materials, and promote their practical applications. In this review, we consider the pyroelectric parameters and the two pyroelectric operation modes. Then based on the operation modes, we review recent achievements in the FE ceramic materials for pyroelectric detection applications, including Pb(Zr,Ti)O3-based, (Bi,Na)TiO3-based, (Sr,Ba)NbO3-based, Pb(Sc,Ta)O3-based, (Ba,Sr)TiO3-based, and Pb(Zr,Sn,Ti)O3-based systems. This review will attempt to provide guidance for further improvements of the pyroelectric properties of these materials and consider future exploration of new FE and other material candidates for use in temperature and infrared sensing/detection applications. [ABSTRACT FROM AUTHOR]

To support practical infrared detector applications, pyroelectric ceramics should exhibit excellent pyroelectric performances, high depolarization temperatures, and good thermal stabilities. In this study, the pyroelectric properties, depolarization behaviors, and thermal stabilities of tetragonal 0.8Bi0.5Na0.5TiO3–0.2BaTiO3 (0.8BNT–0.2BT) ceramics are studied systematically. The samples exhibit high depolarization temperatures (∼209 °C) and excellent thermal stabilities. More importantly, they display high pyroelectric coefficients (p = 2.42 × 10−8 C cm−2 K−1), as well as high voltage responsivity (Fv = 2.68 × 10−2 m2 C−1) and specific detectivity (Fd = 1.53 × 10−5 Pa−1/2) figures of merit at room temperature and 1 kHz. The overall properties of tetragonal 0.8BNT–0.2BT ceramics indicate their potential for application in infrared detectors. [ABSTRACT FROM AUTHOR]

Abstract: High pyroelectric performance and good thermal stability of pyroelectric materials are desirable for the application of infrared thermal detectors. In this work, enhanced pyroelectric properties were achieved in a new ternary (1−x)(0.98(Bi0.5Na0.5)(Ti0.995Mn0.005)O3–0.02BiAlO3)–xNaNbO3 (BNT–BA–xNN) lead‐free ceramics. The effect of NN addition on the microstructure, phase transition, ferroelectric, and pyroelectric properties of BNT–BA–xNN ceramics were investigated. It was found that the average grain size decreased as x increased to 0.03, whereas increased with further NN addition. The pyroelectric coefficient p at room temperature (RT) was significantly increased from 3.87 × 10−8Ccm−2K−1 at x = 0 to 8.45 × 10−8Ccm−2K−1 at x = 0.03. The figures of merit (FOMs), Fi, Fv and Fd, were also enhanced with addition of NN. Because of high p (7.48 × 10−8Ccm−2K−1) as well as relatively low dielectric permittivity (~370) and low dielectric loss (~0.011), the optimal FOMs at RT were obtained at x = 0.02 with Fi = 2.66 × 10−10 m/V, Fv = 8.07 × 10−2 m2/C, and Fd = 4.22 × 10−5 Pa−1/2, which are superior to other reported lead‐free ceramics. Furthermore, the compositions with x ≤ 0.03 exhibited excellent temperature stability in a wide temperature range from 20 to 80°C because of high depolarization temperature (≥110°C). Those results unveil the potential of BNT–BA–xNN ceramics for infrared detector applications. [ABSTRACT FROM AUTHOR]

Electrocaloric response in slim‐like (Ba0.9Ca0.1)(Zr0.2Ti0.8)O3 and square‐like Pb(Zr0.95Ti0.05)O3 hysteresis loops are observed by cycling samples between positive and negative values of electric field, respectively. The slim‐like (Ba0.9Ca0.1)(Zr0.2Ti0.8)O3 ceramics represent a typical electrocaloric response, while the square‐like Pb(Zr0.95Ti0.05)O3 ceramics depict an unusual electrocaloric response. It is worth noting that the unusual electrocaloric response (inverse electrocaloric effect) can be induced by inverse electric field. Furthermore, the highest value of inverse electrocaloric effect is not obtained at negative coercive field but at values that are half of it. With the increase in inverse electric field, the value of induced unusual electrocaloric effect becomes weaker and only positive electrocaloric response is present at higher magnitudes of inverse field. In the present work, the relationship between electrocaloric response and polarization behavior of these two kinds of samples are discussed. [ABSTRACT FROM AUTHOR]

In this paper, the influence of phase evolution on polarization change and electrocaloric response in lead-free (Ba0.9Ca0.1)(Ti1− x Zr x)O3 ceramics ( BCTZ) was systematically investigated. With increasing Zr/Ti ratio, the phase structure and phase transition behavior were greatly changed, resulting in various temperature and electric field dependence of electrocaloric responses. For x=0.05, a peak electrocaloric temperature change 1.64 K (at 130°C) and corresponding entropy change 1.78 J·kg−1·K−1 were obtained for 0-7 kV·mm−1 electric field. Negative electrocaloric temperature change in −0.1 K was obtained below Curie temperature ( Tc), which may be induced by the orthorhombic-tetragonal ferroelectric phase transition. With the increase in x, the peak value of the electrocaloric response decreased but much better temperature stability was observed. Simultaneously the negative electrocaloric response gradually disappeared with the disappearance of the low temperature ferroelectric-ferroelectric phase transition. For x=0.2, electrocaloric response showed good temperature stability ranging from room temperature to 130°C, attributing to the relaxor ferroelectric feature. [ABSTRACT FROM AUTHOR]

PZT95/5 ferroelectric ceramics are widely utilized in pulsed power devices and the remanent polarization Pr of poled PZT95/5 can characterize the shock-driven energy density. However, this remanent polarization is difficult to be measured nondestructively. In this article, a series of pyroelectric tests of poled PZT95/5 ceramics were conducted near room temperature, from 25°C to 20°C. A linear relation between Pr and pyroelectric coefficient p was found, that is, Pr=1190.5( K)× p, which provides an effective way to nondestructively estimate the value of Pr of the poled PZT95/5 ceramics by measuring the pyroelectric coefficient p at room temperature. According to Devonshire's phenomenological theory, this result could be explained by a modified equation: [ABSTRACT FROM AUTHOR]

Highlights: [•] The FR(LT)–FR(HT) phase transition was reduced from 41°C to 24°C with MgO addition. [•] Superior pyroelectric properties were obtained in 0.10wt% MgO-modified sample. [•] The largest p of 65×10−8 Ccm−2 K−1 was achieved at room temperature. [•] Fd of 20×10−5 Pa−1/2 and Fv of 0.91m2C−1 were also attained at room temperature. [ABSTRACT FROM AUTHOR]

Abstract: Sr x Ba1−x Nb2O6 (with x=0.50, 0.45, 0.40 and 0.30) ceramics were synthesized by conventional solid-state method and sintered at 1350°C for 3h. The phase structure, microstructure, dielectric, ferroelectric and pyroelectric properties of obtained ceramics were systematically investigated. Pure tungsten bronze phase could be obtained in all ceramics. The dielectric characteristics showed that SBN ceramic was a relaxor with strong diffuse phase transition and weak frequency dispersion. As Sr molar fraction x increases from 0.30 to 0.50, the transition temperature T C decreased linearly while the diffusivity parameter γ declined from 1.88 to 1.68. The saturated polarization, remnant polarization and pyroelectric coefficient were also found to be enhanced in SBN ceramics with increasing Sr content. The pyroelectric coefficient of about 2×10−8 C/cm2K can be obtained for polarized SBN50 ceramics at room temperature. [Copyright &y& Elsevier]

Hysteresis loops measured at various temperatures were used to study the intrinsic, induced and total pyroelectric responses in Pb(Sc1/2Ta1/2)O3 (PST) ceramics. The intrinsic pyroelectric response was directly measured from the change rate of the remnant polarization with temperature. The induced one was calculated using the data of the dielectric permittivity derived from hysteresis loops. By analyzing the pyroelectric effect of PST ceramics under 30 kV/cm, the results showed that the induced pyroelectric response played a dominant role in the total pyroelectric coefficient near Curie temperature. [ABSTRACT FROM AUTHOR]

Pyroelectric response mechanism of Ba0.70Sr0.30TiO3 ceramics under dielectric bolometer (DB) mode was investigated by dielectric and pyroelectric properties measurement. The variations of total, intrinsic, and induced pyroelectric coefficients (ptot, pint, pind) with temperatures and bias fields were analyzed. pint plays the dominant role to ptot through most of the temperature range and pind will be slightly higher than pint above T0. The essence of the enhancing effect of DC bias field on pyroelectric coefficient can be attributed to the high value of pint. This mechanism is useful for the pyroelectric materials (DB mode) applications. [ABSTRACT FROM AUTHOR]

Both high pyroelectric properties and good temperature stability of ferroelectric materials are desirable when used for applications in infrared thermal detectors. In this work, we report lead-free ternary 0.97(0.99Bi0.5Na0.5TiO3-0.01BiAlO3)-0.03K0.5Na0.5NbO3 (BNT-BA-KNN) ceramics, which not only exhibits a large pyroelectric coefficient (p ∼ 3.7 × 10−8 C cm−2 K−1) and figures of merit (Fi, Fv, and Fd) but also shows excellent thermal stable properties. At room temperature, Fi, Fv, and Fd are determined as high as 1.32 × 10−10 m/V, 2.89 × 10−2 m2/C, and 1.15 × 10−5 Pa−1/2 at 1 kHz and 1.32 × 10−10 m/V, 2.70 × 10−2 m2/C, and 1.09 × 10−5 Pa−1/2 at 20 Hz, respectively. During the temperature range of RT to 85 °C, the achieved p, Fi, Fv, and Fd do not vary too much. The high depolarization temperature and the undispersed ferroelectric-ergodic relaxor phase transition with a sharp pyroelectric coefficient peak value of ∼400 × 10−8 C cm−2 K−1 are suggested to be responsible for this thermal stability, which ensures reliable actual operation. The results reveal the BNT-BA-KNN ceramics as promising lead-free candidates for infrared thermal detector applications. [ABSTRACT FROM AUTHOR]

Cax(Sr0.5Ba0.5)1-xNb2O6 [CSBN(x), x = 0.00, 0.10, 0.15, and 0.20] lead-Free ceramics were prepared by a traditional solid-state reaction technique. Dielectric, ferroelectric, and pyroelectric properties of CSBN(x) lead-Free ceramics were systematically investigated. The pyroelectric properties of CSBN(x) have been enhanced remarkably due to Ca addition and reached the maximum values at x = 0.15, with pyroelectric coefficient of 3.61 × 10-8 C/cm2 K and pyroelectric figure of merit of Fi = 172 pm/V, Fv = 0.021 m2/C, and Fd = 11.5 μPa-1/2, which are superior to other lead-free ferroelectric ceramics. These results indicate the potential of CSBN(x) ceramics for infrared detector applications. [ABSTRACT FROM AUTHOR]

(Pb0.325Sr0.675)TiO3 (PST) ceramics were prepared by a traditional solid-state reaction technique. The dielectric and enhanced pyroelectric properties of PST ceramics were investigated under a DC bias field. The dielectric permittivity and dielectric loss of PST ceramics at Curie temperature were 2.97 × 10-4 and 0.006 without DC bias field, respectively. With a DC electric field of 0-500 V/mm, the maximum pyroelectric coefficient and the largest figure of merit (Fd) of PST ceramics were obtained, about 60 × 10-8 C cm-2 K-1 and 26 × 10-5 Pa-1/2, respectively. PST ceramics with such superior electric field enhanced pyroelectric properties have the potential for uncooled focal plane array detectors application. [ABSTRACT FROM AUTHOR]

Pure and Nb-doped Pb(Zr 1− x Ti x )O 3 ( x = 0.47, 0.48, 0.50) ceramics were prepared by conventional solid-state reaction technique. Dielectric anomalies are observed in both kinds of samples near room temperature. The anomalies could be depressed by donor doping and prefer to be significant in ceramics with tetragonal crystallographic phase. Phase transition mechanism and domain wall pinning effect are proposed to explain this anomaly, and the former is considered as the dominated reason. Further results of the pyroelectric measurements confirm the existence of the ferroelectric–ferroelectric phase transition. [ABSTRACT FROM AUTHOR]

Abstract Currently, there is an urgent need of extraordinary comprehensive pyroelectric materials for the wide application in detectors and energy harvesters. In this study, the (Pb 1–1.5 x La x)(Zr 0.86 Ti 0.14)O 3 (abbreviated as PLZT, x = 0.02, 0.03, 0.04 and 0.05) ceramics located in ferroelectric-antiferroelectric (FE-AFE) phase boundary were designed and synthesized by using conventional solid-state reaction method. The microstructures, phase structures, dielectric, ferroelectric, thermal depolarization and pyroelectric properties of the PLZT ceramics with different La content were investigated thoroughly. The XRD results show that the PLZT ceramics change from FE phase to AFE phase with increasing La content. The significant improvement of pyroelectric coefficient p and figures of merit (FOMs) are achieved in the PLZT ceramics with the increase in La content because of the increased metastable ferroelectric phase under the application of electric field. The (Pb 0.955 La 0.03)(Zr 0.86 Ti 0.14)O 3 (x = 0.03) ceramic exhibits not only high p of 5.2 × 10 − 8 C / cm 2 K and high depolarization temperature (T d) of 179 ℃ but also excellent FOMs with F i = 2.2 × 10 − 10 m / V , F v = 5.0 × 10 − 2 m 2 / C , and F d = 3.47 × 10 − 5 Pa − 1 / 2 . In addition, the highest p of 6.8 × 10 − 8 C / cm 2 K is achieved in (Pb 0.94 La 0.04)(Zr 0.86 Ti 0.14)O 3 (x = 0.04) ceramic. These results demonstrate that the PLZT ceramics of x = 0.03 and 0.04 are promising candidates for pyroelectric applications. [ABSTRACT FROM AUTHOR]

Abstract Pyroelectric energy harvesting has been attracting increasing attention due to its abundance and potential applications. In this work, we comparably investigated the pyroelectric properties of Pb 0.99 (Zr 0.95 Ti 0.05) 0.98 Nb 0.02 O 3 bulk ceramics without (PNZT95/5) and with Mn doping (PNMZT95/5). Compared to PNZT95/5, PNMZT95/5 demonstrated a lower dielectric constant and low rhombohedral - high rhombohedral ferroelectric phase transition temperature (T LH from 37 °C to 27 °C). Moreover, the poling time displayed significant effects on the dielectric and pyroelectric properties of the ceramics. A giant pyroelectric response was obtained for the PNMZT95/5 ceramics, of which the maximum pyroelectric figure of merit F E was 16017 J/(m3K2) after 180 min of poling, which increased 62% compared with the F E for PNZT95/5 (9890 J/(m3K2), far higher than those of other pyroelectric materials as well. PNMZT95/5 ceramics is suggested to be a promising candidate for the thermal energy harvesting applications. Highlights • Giant pyroelectric figure of merit was obtained at room temperature in PNZT95/5 ferroelectric ceramics by doping Mn. • Mn-doping decreased the F RL - F RH phase transition temperature of PNZT95/5 down to room temperature. • Prolonging the poling time of hard PNMZT95/5 ferroelectric ceramics could improve obviously the pyroelectric response. [ABSTRACT FROM AUTHOR]

Abstract: Grain size effect on phase transition, dielectric and pyroelectric properties of BST ceramics under DC bias field was reported for the first time. With the grain size increased by one order of magnitude, phase transition diffuseness parameters δ and γ decreased from 282 to 63 and 1.64–1.33, respectively. This resulted in the dielectric constant maximum increased by 65%, the pyroelectric coefficient maximum and corresponding figure of merit were quadrupled and tripled, respectively. The physical essence of the great size effect can be attributed to a combination of surface effect, mechanical stress effect and extrinsic effect of grain boundary. A well understanding of the grain size effect and its mechanism will be useful for the BaTiO3-based ceramics and other ferroelectrics. [Copyright &y& Elsevier]

Abstract: Pyroelectric properties in alternating hemicyanine (DAEP)/nitrogencrown (NC) Langmuir–Blodgett (LB) films and effects of incorporating barium cations on pyroelectric behaviors have been investigated. Its pyroelectric coefficient measured is found to be 58μCm−2 K−1at 300K. Their dielectric properties have been measured and used to determine the figures of merit in thermal devices. Relative permittivity (ɛ r) and dielectric loss values (tan δ) of pyroelectric films (in the range of 1–100KHz) are found to be 2.34–1.96 and 0.08–0.04, respectively. These data give a maximum pyroelectric figure of merit of 150μCm−2 K−1 in the alternating LB films incorporating barium ions. The effects of different deposition on pyroelectric properties are also discussed in this paper. [Copyright &y& Elsevier]