New lead-free relaxors based on the K0.5Na0.5NbO3–SrTiO3 solid solution

Kosec, Marija; Bobnar, V.; Hrovat, Marko; Bernard, Janez; Malič, Barbara; Holc, Janez

doi:10.1557/jmr.2004.0229

Cited by 178 publications

(85 citation statements)

References 16 publications

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“…By incorporating with different end members, such as LiNbO 3 and SrTiO 3 , the materials show good sinterability and piezoelectric properties. [8][9][10] Lang et al 11 reported the piezoelectric and pyroelectric properties of the KNN-based ceramic. The d 33 and p coefficient were found to be 289 pC / N and 160 C / m 2 K, respectively.…”

Section: Introductionmentioning

confidence: 99%

Lead-free ceramics for pyroelectric applications

Lau

Cheng

Choy

et al. 2008

Journal of Applied Physics

130

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The use of lead-free materials has recently become a very important issue in environmental protection of the earth. Two groups of lead-free ceramics, ͑K 0.5 ,Na 0.5 ͒NbO 3 based ͑KNN͒ and Bi 1−y ͑Na x K 1−x ͒ y TiO 3 based ͑BNKT͒, were studied for their thermal, dielectric, and pyroelectric properties as candidates for pyroelectric sensor applications. The BNKT-based ceramic, ͓Bi 0.5 ͑Na 0.94 K 0.05 Li 0.016 ͒ 0.5 ͔ 0.95 Ba 0.05 TiO 3 ͑BNKLBT͒, shows excellent pyroelectric properties when compared with KNN-based ceramic and lead zirconate titanate. Its properties were measured as follows: pyroelectric coefficient p = 360 C / m 2 K, pyroelectric figure of merit of current, voltage, and detectivity F i = 221 pm/ V, F v = 0.030 m 2 / C, and F d = 14.8 Pa −1/2 . With these outstanding pyroelectric properties, the BNKLBT ceramic can be a promising material for pyroelectric sensor applications. The BNKLBT ceramic with different thicknesses ͑i.e., 0.3, 0.5, and 0.7 mm͒ have been used as the sensing element for fabricating infrared detectors. The current responsivity of the sensors was evaluated as functions of frequency.

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Section: Introductionmentioning

confidence: 99%

Lead-free ceramics for pyroelectric applications

Lau

Cheng

Choy

et al. 2008

Journal of Applied Physics

130

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“…4) From the industrial point of view, conventional sintering is required for mass production. Recently, many researchers have investigated the effects of small amounts of dopants in NKN ceramics such as LiNbO3, 5) LiTaO3, 6) BaTiO3, 7) SrTiO3, 8) and LiSbO3,9) to improve the ceramics' piezoelectric properties. Among these dopants, (Na,K,Li)(Nb,Ta)O3 is a very promising system with improved properties.…”

Section: Introductionmentioning

confidence: 99%

Piezoelectric properties of Li2O excess (Na0.4875K0.4625Li0.05)(Nb0.95Ta0.5)O3 ceramics by conventional sintering method

Kim

Jeong

Kim

et al. 2009

J. Ceram. Soc. Japan

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Lead-free piezoelectric ceramics, (Na0.4875K0.4625Li0.05)(Nb0.95Ta0.05)O3 systems, were developed using the conventional sintering process. The grain growth behavior and piezoelectric properties of the ceramics were investigated. Their sintering temperature was lowered by adding 1 mol% of Li2O as a sintering aid. When the sample was sintered at 1050°C for 4 h with a composition of 1 mol% of excess Li2O (Na0.4875K0.4625Li0.05)(Nb0.95Ta0.05)O3, the electro-mechanical coupling factor (kP) and the piezoelectric coefficient (d33) were found to reach the highest values of 0.42 and 244 pC/N, respectively.

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“…6,7 Although no electrostrictive effect has been reported in KNN 20,21 Counterparts of the above mentioned BNT-, BT-, and KNN-based electrostrictors with pseudocubic/cubic structure can be designed in the center pseudocubic/cubic area of the phase diagram shown in Fig. 1.…”

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confidence: 99%

Phase diagram and electrostrictive properties of Bi0.5Na0.5TiO3–BaTiO3–K0.5Na0.5NbO3 ceramics

Zhang

Yan

Yang

et al. 2010

Applied Physics Letters

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Phase diagram of Bi 0.5 Na 0.5 TiO 3 -BaTiO 3 -K 0.5 Na 0.5 NbO 3 ternary system has been analyzed and ͑0.94− x͒BNT-0.06BT-xKNN ͑0.15Յ x Յ 0.30͒ ceramics have been prepared and investigated. Pseudocubic structures were confirmed by x-ray diffractions and its preliminary Rietveld refinements. P-E, S-E, and S-P 2 profiles ͑where P, E, and S denote polarization, electric field, and strain, respectively͒ indicate electrostrictive behavior of all ceramics. The compositions with x = 0.20 and 0.25 show pure electrostrictive characteristics. The dissipation energy, electrostrictive strain, and electrostrictive coefficient have been determined and compared with other lead-free and lead-containing electrostrictors. The electrostrictive coefficient can reach as high as 0.026 m 4 / C 2 , about 1.5 times of the value of traditional Pb-based electrostrictors. © 2010 American Institute of Physics. ͓doi:10.1063/1.3491839͔Both electrostrictive and piezoelectric ceramics are commercially used in electromechanical devices, such as actuators, space mirrors, etc. Electrostrictors have special advantages over piezoelectrics, because they do not require poling process and there is negligible hysteresis in strain-electric field ͑S-E͒ cycle, which is important for precision position control. [1][2][3] In electrostriction, the sign of the field-induced deformation is independent of the polarity of the field and is proportional to the square of the applied electric fieldwhere Q is the electrostrictive coefficient and P is polarization. 2 In recent years, a lot of attention has been paid to leadfree piezoelectric materials 4,5 but much less effort was devoted to high-performance lead-free electrostrictors. 6-9 One of the reasons might be due to the much smaller commercial market for high performance electrostrictors than for piezoelectric devices. Another reason might be due to the lack of public awareness on the fact that most of currently used electrostrictors are also lead based materials. With increasing pressure from environmental legislations, lead-free piezoelectric and electrostrictive materials are urgently in demand. Therefore, it is just as important to study lead-free electrostrictive materials as lead-free piezoelectric materials.Electrostriction is a general property of all dielectric materials but it is significantly large in ferroelectrics just above the Curie temperature ͑T c ͒, where an electric field can induce energetically unstable ferroelectric phase. In relaxor ferroelectrics, the electrostrictive strain can be kept at a relatively high level in a wide temperature range, because of the diffused phase transition. 2 If the phase transition temperature of a relaxor ferroelectrics is close to room temperature ͑RT͒, the electrostrictive effect can be very large at RT. Therefore, one may adjust the composition or dopants in lead-free relaxor ferroelectrics to produce pseudocubic/cubic crystal structure at RT, which might produce good lead-free electrostrictors. Recently reported electrostrictors, ͑Sr 1−y−x Na y Bi x ͒Ti...

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New lead-free relaxors based on the K_0.5Na_0.5NbO₃–SrTiO₃ solid solution

Cited by 178 publications

References 16 publications

Lead-free ceramics for pyroelectric applications

Lead-free ceramics for pyroelectric applications

Piezoelectric properties of Li2O excess (Na0.4875K0.4625Li0.05)(Nb0.95Ta0.5)O3 ceramics by conventional sintering method

Phase diagram and electrostrictive properties of Bi0.5Na0.5TiO3–BaTiO3–K0.5Na0.5NbO3 ceramics

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