Electric Conductivity of Ferroelectric Pb₅Ge₃O₁₁

抄録

Electric conductivity of ferroelectric Pb₅Ge₃O₁₁ single crystal was measured near the Curie point, θ_f=177°C. An a.c. method was adopted at very low frequency range of several Hz. At the low frequency limit the conductivity represents approximately the bulk d.c. conductivity. Near and above the Curie point, the crystal is semiconductive, σ∼10⁻⁶ Ω⁻¹m⁻¹. Activation energies estimated from the conductivity data taken at 1.8 Hz, along c-axis and a-axis, respectively, are ΔU_c=1.6₀ eV, ΔU_a=1.4₄ eV in the ferroelectric phase, and ΔU_c=1.4₁ eV, ΔU_a=1.2₈ eV in the paraelectric phase, respectively.