Electron-spin-resonance investigation of ferroelectric lead titanate

Abstract

Electron-spin-resonance measurements have been made on axially symmetric spectra of ${\mathrm{Fe}}^{3+}$ in ${\mathrm{PbTiO}}_3$. Two spectral systems corresponding to two different environments of the ${\mathrm{Fe}}^{3+}$ ion replacing a ${\mathrm{Ti}}^{4+}$ ion have been found. The spin-Hamiltonian constants $D=1.187\mathrm{}\pm 0.002$ ${\mathrm{cm}}^{-1\mathrm{}}$, $a=0.020\mathrm{}\pm 0.007$ ${\mathrm{cm}}^{-1\mathrm{}}$, $F=-0.017\mathrm{}\pm 0.01$ ${\mathrm{cm}}^{-1\mathrm{}}$ for the system with narrow linewidth (∼ 100 G) and $D=1.150\mathrm{}\pm 0.003$ ${\mathrm{cm}}^{-1\mathrm{}}$, $a=0.022\mathrm{}\pm 0.01$ ${\mathrm{cm}}^{-1\mathrm{}}$, $F=-0.02\mathrm{}\pm 0.01$ ${\mathrm{cm}}^{-1\mathrm{}}$ for the system with wide linewidth (∼ 300 G) have been found at -188°C. The temperature dependence of the spin-Hamiltonian constants $D$ have been measured between liquid-nitrogen and room temperatures. The wide-line spectrum has been identified to be due to ferroelectric distortion whereas the narrow-line spectrum arises from a missing oxygen ion due to charge compensation. These results have been compared with an equivalent study in barium titanate; the major intent being to relate the magnitude of polarization to spin-Hamiltonian constants.