Dwight Viehland , Virginia Polytechnic Institute and State University, DMR 0806592

1. Competing interactions in Pb-free piezoelectricsDwight Viehland, Virginia Polytechnic Institute and State University, DMR 0806592 Neutron diffuse scattering studies of Na0.5Bi0.5TiO3 (or NBT) and Na0.5Bi0.5TiO3-5.6%BaTiO3 (or NBT-5.6%BT) crystals were performed at BT-9 at NIST. The figure to the left shows logarithmic plots of the neutron elastic diffuse scattering intensity contours around (100) and (110) Bragg peaks for NBT at 25oC. The scan reveals presence of butterfly-like patterns in the diffuse scattering which had lobes oriented along the <110>, as out-lined by the red-dotted. In addition, we found even broader diffuse scattering lobes along the <100>, as out-lined by the red-solid lines. These findings indicate the presence of both tetragonal-like (i.e., {001}) and rhombohedral-like (i.e., {110}) short range polar orderings for NBT. With temperature increasing (data not shown), the diffuse scattering intensity from rhombohedral-like (i.e.,{110}) short range polar orderings became weaker.

2. Synthesis of (1-x)NBT-xBT; x=0.07 textured ceramics Dwight Viehland, Virginia Polytechnic Institute and State University, DMR 0806592 NBT template Fractograph NBTBT composition near morphotropic phase boundary was textured using TGG method. For this NBT platelets were used as templates. The randomly oriented specimen was found to show d33 ~160 pC/N, which was increased up to 322 pC/N for 92 % (100) oriented specimen. Thus, textured NBTBT specimen was found to show almost double piezoelectric response than that of its randomly oriented counterpart. EBSD Pole figure EBSD orientation map Temperature dependence of relative permittivity and loss tangent indicated the depoling temperature (Td) of ~ 110oC and temperature of maximum relative permittivity (Tm) as ~ 300oC.