Pb displacements in Pb(Zr,Ti)O3perovskites

Electron-paramagnetic-resonance spectroscopy, band-structure calculations, polarization-voltage measurements, and charge injection experiments are used to show that ${\mathrm{Pb}}^{2+}$ ion displacements are critical to the ferroelectric behavior of Pb(Zr,Ti)${\mathrm{O}}_3$. The displacements of the ${\mathrm{Pb}}^{2+}$ ions are followed by analyzing the hyperfine and superhyperfine interactions of the photoinduced ${\mathrm{Pb}}^{3+}$ center. The ferroelectric contribution of ${\mathrm{Pb}}^{2+}$ arises because Pb retains its 6s valence electrons which then hybridize with the O 2p states to create a high effective charge. This contrasts with other perovskites in which the A ion in other ${\mathit{ABO}}_3$ perovskite structures possesses an inert gas configuration and retains its classical ionic charge. © 1996 The American Physical Society.