Microscopic and macroscopic transport properties in Nb-doped BaTiO<sub>3</sub>ceramics

Gillot, C.; Spira, Micha Ε.; Michenaud, J-P.

doi:10.1080/00150199408007502

Cited by 3 publications

(2 citation statements)

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“…The compositional design is a key component to achieve the desired material electrical properties. In the present work, Y 2 O 3 and Nb 2 O 5 , which are the commonly used donors individually [9,10], were added simultaneously as the double donors to reduce the roomtemperature resistivity [11]. The Y 3+ and Nb 5+ ions substituted Ba 2+ and Ti 4+ ions in the lattices to induce grains semiconductivity.…”

Section: Resultsmentioning

confidence: 99%

Experimental determination of intrinsic parameters in double-donor-doped (Ba_0.92Sr_0.08)TiO₃-based positive temperature coefficient ceramics

et al. 2004

J. Phys.: Condens. Matter

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In the present work, double-donor-doped (Ba 0.92 Sr 0.08 )TiO 3 -based positive temperature coefficient (PTC) ceramics were fabricated for potential application in an over-current protector. The electrical properties of the materials were also characterized. Using the experimental results obtained, theoretical models on electrical properties were studied, and the intrinsic parameters were determined. The relationship between the intrinsic parameters, the materials variables and the electrical properties was discussed. It was noted that the addition of double donors Y 2 O 3 + Nb 2 O 5 could result in relatively low room-temperature resistivity, in particular, 30 cm at the sintering temperature of 1230 • C. Within the investigated working temperature range, the grain-boundary potential barrier at a fixed measuring temperature decreased with increasing sample sintering temperature. The evaluated effective donor concentration and surface acceptor state density were in good agreement with the reported values in the literature. A parameter was introduced based on these two variables to represent the resistivity jump. The depletion layer thickness was determined to be in the submicron range. The present work is believed to be the first report to determine, based on the experimental data, all the essential intrinsic parameters for double-donor-doped PTC ceramics.

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Section: Resultsmentioning

confidence: 99%

Experimental determination of intrinsic parameters in double-donor-doped (Ba_0.92Sr_0.08)TiO₃-based positive temperature coefficient ceramics

et al. 2004

J. Phys.: Condens. Matter

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“…Despite the method. 11 A 2000 Å thick Al film is evaporated on a 5000 Å Heywang model based on grain boundary potential barriers 1,2 thick Cr layer. The metallic tracks are elecrically isolated from proposed in the 1960s, understanding of the microscopic origin the BaTiO 3 except in a limited area at the border between of this anomaly of resistivity still remains unclear.…”

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confidence: 99%

Microscopic Origin of the PTC Effect in Niobium‐Doped Barium Titanate

Gillot

Michenaud

Baukens

et al. 1997

Journal of the American Ceramic Society

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The influence of bulk conductivity on the PTC effect of calcinated at 800ЊC. The sol-gel method is based on controlled hydrolysis of a titanium alkoxide under basic conditions proNb-doped barium titanate is investigated. Both macroscopic and microscopic resistance measurements are performed as duced by hydrated barium hydroxide in the solid state. 8,9 Niobium oxide, citrate, or alkoxide is added in adequate propora function of temperature. The macroscopic measurement refers to the whole sample while the microscopic one, tions (0.1 to 0.4 at.%) as donor dopant and manganese oxide (less than 0.1 at.%) as acceptor dopant for the solid-state reacobtained by photolithography techniques, concerns only several grains. The results show that the increase of resistion method only. The powders prepared by the solid-state and citrate methods were pressed at 400 MPa, sintered at 1400ЊC tivity occurs in two steps: first, an abrupt variation at the for 30 min, then annealed at 1300Њ and at 1220ЊC, both for 30 Curie temperature T c which is ascribed to the phase transimin. The powders prepared by the sol-gel method were sintered tion in the bulk; second, a continuous increase above T c at 1200ЊC for 2 h followed by furnace cooling. which is usually explained from grain boundary potentialMacroscopic electrical measurement is performed as a funcbarriers only. However, our results suggest that a nonneglition of temperature on the ceramic samples coated with a gible contribution of the bulk is also involved in this increase "French alloy" (42% Bi-18.1% In-10.6% Sn-8.3% Cd-21% above T c .Pb) which is well known 10 to ensure ohmic contact. On the other hand, using photolithographic techniques, microscopic

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Effect of additives on the electrical properties of a (Ba0.92Sr0.08)TiO3-based positive temperature coefficient resistor

et al. 2002

Journal of the European Ceramic Society

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Microscopic and macroscopic transport properties in Nb-doped BaTiO₃ceramics

Cited by 3 publications

References 15 publications

Experimental determination of intrinsic parameters in double-donor-doped (Ba_0.92Sr_0.08)TiO₃-based positive temperature coefficient ceramics

Experimental determination of intrinsic parameters in double-donor-doped (Ba_0.92Sr_0.08)TiO₃-based positive temperature coefficient ceramics

Microscopic Origin of the PTC Effect in Niobium‐Doped Barium Titanate

Effect of additives on the electrical properties of a (Ba0.92Sr0.08)TiO3-based positive temperature coefficient resistor

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Microscopic and macroscopic transport properties in Nb-doped BaTiO3ceramics

Cited by 3 publications

References 15 publications

Experimental determination of intrinsic parameters in double-donor-doped (Ba0.92Sr0.08)TiO3-based positive temperature coefficient ceramics

Experimental determination of intrinsic parameters in double-donor-doped (Ba0.92Sr0.08)TiO3-based positive temperature coefficient ceramics

Microscopic Origin of the PTC Effect in Niobium‐Doped Barium Titanate

Effect of additives on the electrical properties of a (Ba0.92Sr0.08)TiO3-based positive temperature coefficient resistor

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Microscopic and macroscopic transport properties in Nb-doped BaTiO₃ceramics

Experimental determination of intrinsic parameters in double-donor-doped (Ba_0.92Sr_0.08)TiO₃-based positive temperature coefficient ceramics

Experimental determination of intrinsic parameters in double-donor-doped (Ba_0.92Sr_0.08)TiO₃-based positive temperature coefficient ceramics