New morphotropic phase boundary (MPB) piezoelectrics, with ferroelectric phase transition (T c ) exceeding that of PbZrO 3 -PbTiO 3 (PZT), were investigated. Based on a perovskite tolerance factor-T c relationship, new high T c MPB systems were projected in the Bi(Me)O 3 -PbTiO 3 system, where Me is a relatively large B +3 -site cation. For the (1 − x)BiScO 3 -(x)PbTiO 3 solid solution, a MPB was found at x-0.64 separating the rhombohedral and tetragonal phases, with correspondingly enhanced dielectric and piezoelectric properties. A transition temperature T c of ∼ 450 • C was determined with evidence of T c 's on the order of ≥ 600 • C in the BiInO 3 and BiYbO 3 analogues, though issues of perovskite stability remain for the smaller tolerance end-member systems.

No abstract

Electric-field-induced phase transitions in rhombohedral Pb(Zn1/3Nb2/3)1-xTixO3 Noheda, Beatriz; Zhong, Z.; Cox, D.E.; Shirane, G.; Park, S-E.; Rehrig, P. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. 5% and 8% show that an electric field applied along the ͓001͔ direction induces the tetragonal phase, as proposed by Park and Shrout. Our experiments reveal that in PZN-4.5%PT such a phase change occurs via a third phase with monoclinic symmetry M A , which is observed at intermediate field values. This is in agreement with first-principles calculations by Fu and Cohen predicting the rotation of the polarization between the rhombohedral and tetragonal phases in this material. A different polarization path between the rhombohedral and tetragonal phases, through a second monoclinic phase M C , has been previously reported in PZN-8%PT. The microscopic characterization of these crystals allows us to explain the ultrahigh macroscopic strain observed in PZN-x%PT under an electric field. Furthermore, some unusual scattering profiles displayed by exceptionally good crystals provide experimental evidence of the high anharmonicities and near degeneracy of the different phases in these extremely deformable materials.

No abstract