B. Guiffard et al., Effects of fluorine-oxygen substitution on the dielectric and electromechanical properties of lead zirconate titanate ceramics, J APPL PHYS, 86(10), 1999, pp. 5747-5752
In this study, a fluorine-oxygen substitution in lead zirconate titanate (P
ZT) ceramics with a nominal composition of Pb-0.89(Ba, Sr)(0.11)(Zr0.52Ti0.
48)O-3 (PZT) doped with 1% MgO is proposed. The evolution of four dielectri
c and electromechanical coefficients-epsilon(r), tg delta, d(33), and Q(m)-
with increasing fluorine concentration showed that (MgO and F)-doped PZT ce
ramics are harder than only MgO-doped PZT (0 at. % F). The influence of the
F-O substitution on the temperature dependence of the frequency constant N
-33 and the stress dependence of the piezoelectric coefficient d(33) was in
vestigated. A hysteretic free response of N-33 and the lowest stress depend
ence of d(33) were obtained for the (MgO and 4 at. % F)-doped PZT specimen.
This material also exhibits the highest Q(m) in the (MgO and F)-doped PZT
family and seems to be stoichiometric and without oxygen vacancies. For com
parison, both the temperature and stress dependences of two commercial PZT
ceramics are shown. The study of the influence of the Zr/Ti ratio on the te
mperature dependence of N-33 revealed that fluorine stabilizes the rhombohe
dral phase/tetragonal phase interface. Both types of stability, versus temp
erature and uniaxial mechanical stress, may be linked to the domain wall co
nfiguration stabilization by Mg2+-F- dipoles which are less mobile than Mg2
+-V-O ones. (C) 1999 American Institute of Physics. [S0021-8979(99)00822-1]
.