PB DISPLACEMENTS IN PB(ZR,TI)O-3 PEROVSKITES

Electron-paramagnetic-resonance spectroscopy, band-structure calculati ons, polarization-voltage measurements, and charge injection experimen ts are used to show that Pb2+ ion displacements are critical to the fe rroelectric behavior of Pb(Zr,Ti)O-3. The displacements of the Pb2+ io ns are followed by analyzing the hyperfine and superhyperfine interact ions of the photoinduced Pb3+ center. The ferroelectric contribution o f Pb2+ arises because Pb retains its 6s valence electrons which then h ybridize with the O 2p states to create a high effective charge. This contrasts with other perovskites in which the A ion in other ABO(3) pe rovskite structures possesses an inert gas configuration and retains i ts classical ion charge.