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1

Microstructural Analysis and Transport Properties of RuO_2-Based Thick Film Resistors

100%

Gabáni S., Flachbart K., Pavlík V., Pietriková A., Gabániová M.

Acta Physica Polonica A

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2008

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vol. 113

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issue 1

625-628

EN

RuO_2-based low temperature sensors appear as very good secondary thermometers, mainly in the temperature range below 4.2 K. This is due to their high temperature sensitivity and small magnetoresistance. Both properties are strongly influenced by the manufacturing process (mainly by firing temperature and firing time). In our contribution we show that the microstructure of sensors and the temperature dependence of their resistance R(T) down to 50 mK, in case when all sensors are prepared from the same paste, can be strongly influenced by change of the firing temperature from 800°C to 900°C. The paper also presents results on the X-ray microanalysis and the analysis of electrical conductivity of these sensors.

2

Application of High Permittivity Bismuth Copper Titanate in Multilayer Capacitors

100%

Szwagierczak D., Kulawik J.

Acta Physica Polonica A

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2012

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vol. 121

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issue 1

119-121

EN

A nonferroelectric high permittivity compound with the perovskite structure, Bi_{2/3}Cu_3Ti_4O_{12}, was synthesized at 900°C. The ceramic powder and appropriate organic additives were used for preparation of a slurry for tape casting. The obtained green tapes were smooth, flexible, and with a uniform thickness of 25 μm after drying at 50°C. Ag electrodes were screen printed on green rectangular sheets cut by a laser. Subsequent operations were screen printing of Ag internal electrodes, stacking of green sheets, isostatic lamination, cutting, deposition of external terminations and co-firing of dielectric and conductive layers at 850°C. Scanning electron microscopy observations showed well sintered, dense, fine-grained microstructure of ceramic layers and good cooperation with the electrodes made of commercial Ag paste. Capacitance and dissipation factor of multilayer capacitors were examined in the temperature range from - 55 to 330C at frequencies 10 Hz-2 MHz. The fabricated multilayer capacitors exhibit high capacitance and relatively low temperature coefficient of capacitance in the temperature range from - 55 to 110°C. The obtained lead-free high permittivity nonferroelectric material Bi_{2/3}Cu_3Ti_4O_{12} is a spontaneously formed internal barrier capacitor. This material seems to be a promising alternative for conventional lead-based relaxor dielectrics in multilayer ceramic capacitors.

3

Multilayer Perovskite-Based Thermistors Fabricated by LTCC Technology

100%

Kulawik J., Szwagierczak D., Witek K., Skwarek A., Gröger B.

Acta Physica Polonica A

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2013

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vol. 123

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issue 2

436-438

EN

In this work, single-phase La_{0.7}Sr_{0.3}Zr_{0.5}Co^{2+}_{0.2}Co^{3+}_{0.3}O_3 and La_{0.8}Sr_{0.2}Ti_{0.5}Co^{2+}_{0.3}Co^{3+}_{0.2}O_3 ceramics with the stable perovskite structure were utilized for fabrication of multilayer negative temperature coefficient thermistors. The number and thicknesses of ceramic layers were adjusted to attain suitable resistances in a desired temperature range. Scanning electron microscopy studies revealed a dense, fine-grained microstructure of ceramic layers, lack of delaminations and cracks at ceramic layer-conductive layer boundaries and a good cooperation with conductive layers. The temperature coefficients of resistance of the fabricated multilayer thermistors were changing from - 13 to - 1%/K in the temperature range from - 55 to 400C.

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3 Acta Physica Polonica A

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1 Flachbart K.

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1 Pavlík V.

1 Pietriková A.

1 Skwarek A.

1 Witek K.

Microstructural Analysis and Transport Properties of RuO_2-Based Thick Film Resistors

Application of High Permittivity Bismuth Copper Titanate in Multilayer Capacitors

Multilayer Perovskite-Based Thermistors Fabricated by LTCC Technology