Enhanced dielectric and piezoelectric properties in Na0.5Bi4.5Ti4O15 ceramics with Pr-doping.

The bismuth layer-structured Na 0.5 Bi 4.5- x Pr x Ti 4 O 15 ( x  = 0, 0.1, 0.2, 0.3, 0.4, and 0.5) (NBT- x Pr 3+ ) ceramics were fabricated using the traditional solid reaction process. The effect of different Pr 3+ contents on dielectric, ferroelectric and piezoelectric properties of Na 0.5 Bi 4.5 Ti 4 O 15 ceramics were investigated. The grain size of Pr 3+ -doping ceramics was found to be smaller than that of pure one, the maximum dielectric constant and Curie temperature T c gradually decreased with increasing Pr 3+ contents, and the dielectric loss decreased at high temperature by Pr 3+ -doping. Moreover, the activation energy ( E a ), resistivity ( Z’ ), remanent polarization (2 P r ) and piezoelectric constant ( d 33 ) increased by Pr 3+ -doping. The NBT- x Pr 3+ ceramics with x  = 0.3 achieved the optimal properties with the maximum dielectric constant of 1109.18, minimum loss of 0.00822 (250 kHz), E a of 1.122 eV, Z’ of 7.9 kΩ cm (725 ºC), d 33 of 18 pC/N, 2 P r of 12.04 μC/cm 2 . The enhancement was due to the addition of Pr 3+ which suppressed the decreasing of resistivity at high temperature and made it possible for NBT- x Pr 3+ ceramics to be poled in perpendicular direction, implying that it is a great improvement for Na 0.5 Bi 4.5 Ti 4 O 15 ceramics in electrical properties. [ABSTRACT FROM AUTHOR]