K. Harada et al., EFFECT OF FIRED AG ELECTRODES ON ELECTRICAL-PROPERTIES OF A PB[(ZN1 3NB2/3)(0.91)TI-0.09]O-3 SINGLE-CRYSTAL/, Nippon Seramikkusu Kyokai gakujutsu ronbunshi, 106(1), 1998, pp. 116-118
The dielectric constants and electromechanical coupling coefficients o
f Pb[(Zn1/3Nb2/3)(0.91)Ti-0.09]O-3 (PZNT91/9) single crystals with dif
ferent electrode materials have been investigated. Two types of electr
odes, sputtered Au/Ti and fired Ag, were applied to single crystals of
PZNT91/9, The dielectric constant K at room temperature was 8000 for
samples with Au/Ti electrodes. However, the sample with fired Ag elect
rodes had a lower K value of 1000. After electrical poling, the sample
with Au/Ti electrodes had an electromechanical coupling coefficient k
(t) of 52.7%, while the sample with fired Ag electrodes showed a relat
ively high k(t) value of 61.4%, This could be the result of the large
amount of mechanical stress in the fired Ag electrode, Spontaneous int
rinsic polarization of the rhombohedral system may be reoriented paral
lel or antiparallel along one particular direction because of the mech
anical stress.