| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1296951 | Solid State Ionics | 2008 | 4 Pages |
Electrical and dielectric properties, ionic transference numbers, thermal conductivity, and microhardness of Bi5.8PO11.2 (BPO) and Bi4Ge3O12 (BGO) single crystals are studied. Pr3+ and Er3+ are used as dopants in BGO. BPO crystals are mixed electron-ionic conductors (up to 500 °C, ti = 0.14 ± 0.01). The ionic conductivity, σ, and relative static permittivity, εs, are slightly anisotropic, their highest values, σ = 6 · exp (− 0.64 eV/kT) and εs = 50 ± 1, are found along the growth direction [1¯01]. BGO crystals have a low conductivity (1.5 10− 6 S/cm, at 600 °C) of a dominant ionic character (ti = 0.83 ± 0.02). Doping with rare earth ions decreases the conductivity significantly. The static relative permittivity of both “pure” and doped BGO is equal to 16.4 ± 0.1. The thermal conductivity and microhardness of BGO are equal to 4.5 ± 0.1 W/Km or 5.5 ± 0.1 kN/mm2, respectively. A slight impurity hardening takes place.
