Fabrication and positive temperature coefficient of resistivity properties of semiconducting ceramics based on the BaTiO3–(Bi1/2K1/2)TiO3 system

Takeda, Hiroaki; Harinaka, H.; Shiosaki, Tadashi; Zubair, M.; Leach, C.; Freer, Robert; Hoshina, Takuya; Tsurumi, Takaaki

doi:10.1016/j.jeurceramsoc.2009.08.009

Cited by 32 publications

(17 citation statements)

References 17 publications

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“…XAFS studies by Lebedev at al. [13] indicated a displacement of Pb atoms from the A lattice site in the ABO 3 perovskite structure by~0.15 Å and a strong distortion of the oxygen environment as the main factors responsible for the appearance of ferroelectricity in the temperature range above~400 K, that is the Curie point of pure BaTiO 3 [14][15][16][17]. According to the literature data [4] the temperatures of the transitions from tetragonal to orthorombic and from orthorhombic to rhombohedral phases are lowered due to an addition of the Pb ions resulting in a broadening of the dielectric anomaly in the vicinity of room temperature.…”

Section: Introductionmentioning

confidence: 99%

Effect of cobalt doping on the dielectric response of Ba0.95Pb0.05TiO3 ceramics

et al. 2013

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Dielectric response of Ba 0.95 Pb 0.05 TiO 3 ceramics doped with 0.1 and 1 wt.% of Co 2 O 3 , synthesized by conventional high-temperature method, was studied in wide temperature and frequency range. The temperature dependences of the real and the imaginary parts of dielectric permittivity of the ceramics were compared with those of BaTiO 3 and Ba 0.95 Pb 0.05 TiO 3. The addition of Co 3+ ions results in a broadening of dielectric anomalies related to the transition to paraelectric cubic phase, and the structural transition between the tetragonal and the orthorhombic phases. At low temperatures (125-200 K) the dielectric absorption of Co-doped Ba 0.95 Pb 0.05 TiO 3 ceramics was found to exhibit relaxor-like properties. The dielectric response has been found to contain the contributions characteristic of fluctuations of the polar nanoregion boundaries and reorientations of the dipole moments between allowed directions in the nanoregions in the rhombohedral and the orthorhombic phases. The behavior speaks in favor of ordering of polar defects in the host lattice of Ba 0.95 Pb 0.05 TiO 3 in a form polar nanoregions .

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Section: Introductionmentioning

confidence: 99%

Effect of cobalt doping on the dielectric response of Ba0.95Pb0.05TiO3 ceramics

et al. 2013

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“…T S has shifted by 22, 24 and 25°C towards higher temperatures in comparison to that of Nb-doped BT for BBKT5, BBKT5-AST and BBKT5-ASTMn respectively. In our previous study, 18) as sintered BBKT5 ceramic was found to remain as single phase and exhibited a tetragonal symmetry with perovskite structure with a-axis reduced by 0.08% from that of pure BT, indicating that 5 mol % BKT forms a solid solution with BT and explains the observed shift in T S with BKT addition.…”

Section: Results and Discussion 31 Electrical Property And Microstrmentioning

confidence: 81%

Bulk and conductive mode investigations of Pb free PTCR ceramics with high switch temperature

Zubair

Takeda

Leach

et al. 2013

J. Ceram. Soc. Japan

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Lead free positive temperature coefficient of resistivity (PTCR) thermistors with switching temperature T S of 155°C were synthesized from 0.95BaTiO 3 0.05(Bi 1/2 K 1/2 )TiO 3 solid solution for high temperature applications, utilizing the conventional ceramic fabrication technique, which involved sintering ceramics in N 2 flow followed by air annealing. Addition of sintering aid AST (Al 2 O 3 :SiO 2 :TiO 2 with 4:9:3 molar ratio) and Mn improved the bulk PTCR response. Impedance spectroscopy analysis confirmed the bulk T S and revealed a third ferroelectric resistance-capacitance (RC) element along with a semiconducting grain and PTCR active ferroelectric grain boundary. The investigation of local electrical activity adopting hot-stage conductive mode microscopy revealed the existence of type-I grain boundary-electron beam induced current (GB-EBIC) contrast pertinent to the presence of negatively charged interfaces neighbored with compensating positive space-charge layers typical of double Schottky barrier within the Pb free PTCR system.

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“…(1x)BaTiO 3 -xK 0.5 Bi 0.5 TiO 3 (0.05 ≤ x ≤ 0.1) PTCR materials were sintered in inert nitrogen atmosphere in order to provide semiconductor properties [16]. It was found that semiconductor properties in (1x)BaTiO 3  xK 0.5 Bi 0.5 TiO 3 (x = 0.05) are due to the partial reduction of titanium ion (Ti 4+ → Ti 3+ ) during sintering of ceramics in reducing atmosphere [17,18].…”

Section: Introductionmentioning

confidence: 99%

Semi-oxalate synthesis of (1−x)BaTiO3−xM0.5Bi0.5TiO3 (M = Li, Na, K) PTCR materials

et al. 2016

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(1x)BaTiO 3 -xM 0.5 Bi 0.5 TiO 3 (M = Li, Na, K) solid solutions were prepared using BaTiO 3 pre-synthesized by oxalate method. The stability limits of (1x)BaTiO 3 -xLi 0.5 Bi 0.5 TiO 3 solid solutions have been established. It was shown that increase in M 0.5 Bi 0.5 TiO 3 concentration results in reduction of ceramic grain size in the (1x)BaTiO 3 xM 0.5 Bi 0.5 TiO 3 (M = Li, Na, K) system. It was found that the positive temperature coefficient of resistance (PTCR) effect in lead-free materials is due to the presence of a semiconductor core, which is formed by sintering under reducing atmosphere, and dielectric grain boundaries, formed on additional oxidation in air. The use of barium titanate, pre-synthesized by oxalate method, in the synthesis of solid solutions reduced the sintering temperature of ceramics compared with solid state reaction technique. By comparing the electrical properties of the synthesized lead-containing and lead-free materials, it has been shown that lead-free materials exhibit better electrical properties for practical use compared with lead-containing materials.

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Fabrication and positive temperature coefficient of resistivity properties of semiconducting ceramics based on the BaTiO3–(Bi1/2K1/2)TiO3 system

Cited by 32 publications

References 17 publications

Effect of cobalt doping on the dielectric response of Ba0.95Pb0.05TiO3 ceramics

Effect of cobalt doping on the dielectric response of Ba0.95Pb0.05TiO3 ceramics

Bulk and conductive mode investigations of Pb free PTCR ceramics with high switch temperature

Semi-oxalate synthesis of (1−x)BaTiO3−xM0.5Bi0.5TiO3 (M = Li, Na, K) PTCR materials

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