Solid State Science and Technology, Vol. 19, No 1 (2011) 56-61

ISSN 0128-7389

56

IMPEDANCE STUDIES ON THE SUB-MICRON GRAIN Yb-DOPED

Ba(Ce,Zr)O3 CERAMICS AT INTERMEDIATE TEMPERATURES

N. Osman1,*, I. A. Talib2 and H. A. Hamid1

1Faculty of Applied Sciences, Universiti Teknologi MARA,

02600 Arau, Perlis, Malaysia

2 School of Applied Physics, Faculty of Science and Technology,

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

 

ABSTRACT

A ceramic of Ba(Ce0.6Zr0.4)0.95Yb0.05O2.975 was prepared by the Pechini method.

Morphology of the fractured surface of sintered pellet was observed using a scanning

electron microscope. The sample formed clear and compact grains with submicron

sizes. Impedance data were collected using a high frequency response analyzer under

wet hydrogen in the temperature range from 200 to 800 oC. At T ≤ 250oC, the high

frequency arc corresponding to grain response, the mid-frequency arc due to the grain

boundary response, and low frequency arc attributed to the electrode/electrolyte

interface were observed. Above 300oC, the grain resistance was obtained from the

intercept of the grain boundary arc with the real axis at high frequency. It was also

noticed that above 300oC, the Z-imaginary data at high frequencies changed its sign to

positive values. All the responses were resolved by the fitting procedure using an

equivalent circuit representing the brick-layer model. Arrhenius plot of proton

conductivity and capacitances associated with the grain and grain boundary of

Ba(Ce0.6Zr0.4)0.95Yb0.05O2.975 are also presented.

 

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