A range of compounds, Bi2CoxV1-xO5.5-3x/2, (where x ranged from 0.07 to 0.20), was synthesized and the dependence of the electrical conductivity upon the chemical composition was investigated. It was found that the conductivity of the compounds at low temperatures increased with increasing x-value, reached a maximum at x = 0.13, and decreased at higher x-values (table 28). On the other hand, the conductivity at high
temperatures decreased continuously with increasing x-value.
W.Bogusz, F.Krok, D.Bangobango, W.Jakubowski: Solid State Phenomena, 1994, 39-40, 251-4
Table 29
Ionic Conductivity of Bi2V0.9Cu0.1O5.35
Theoretical Density (%) | Temperature (C) | σ (S/cm) | E (eV) |
85.9 | 200 | 0.20 x 10-3 | 0.63 |
85.9 | 400 | 1.46 x 10-2 | 0.63 |
85.9 | 600 | 1.05 x 10-1 | 0.48 |
93.7 | 200 | 0.30 x 10-3 | 0.62 |
93.7 | 400 | 1.68 x 10-2 | 0.62 |
93.7 | 600 | 9.97 x 10-2 | 0.46 |
92.1 | 200 | 0.70 x 10-3 | 0.53 |
92.1 | 400 | 1.96 x 10-2 | 0.53 |
92.1 | 600 | 1.13 x 10-1 | 0.47 |
87.9 | 200 | 0.30 x 10-3 | 0.59 |
87.9 | 400 | 1.46 x 10-2 | 0.59 |
87.9 | 600 | 9.25 x 10-2 | 0.47 |
92.9 | 200 | 0.20 x 10-3 | 0.70 |
92.9 | 400 | 1.70 x 10-2 | 0.70 |
92.9 | 600 | 9.74 x 10-2 | 0.56 |
95.6 | 200 | 0.40 x 10-3 | 0.58 |
95.6 | 400 | 1.93 x 10-2 | 0.58 |
95.6 | 600 | 1.11 x 10-1 | 0.46 |
97.3 | 200 | 0.30 x 10-3 | 0.51 |
97.3 | 400 | 1.61 x 10-2 | 0.51 |
97.3 | 600 | 8.62 x 10-2 | 0.51 |
96.8 | 200 | 0.30 x 10-3 | 0.60 |
96.8 | 400 | 1.87 x 10-2 | 0.60 |
96.8 | 600 | 1.13 x 10-1 | 0.52 |
Table 30
Conductivity of Bi2V0.9Cu0.1O5.35
Orientation | Thermal Cycle | T (K) | 500K (S/cm) | 900K (S/cm) |
parallel | first cooling | 630-370 | 4.3 x 10-5 | - |
parallel | second heating | 370-650 | 5.0 x 10-5 | - |
parallel | second cooling | 630-380 | 2.1 x 10-5 | - |
parallel | first cooling | 960-700 | - | 0.26 |
parallel | second heating | 840-990 | - | 0.24 |
parallel | second cooling | 990-710 | - | 0.25 |
perpendicular | first cooling | 625-470 | 5.2 x 10-8 | - |
perpendicular | second heating | 480-660 | 4.5 x 10-8 | - |
perpendicular | second cooling | 625-465 | 3.9 x 10-8 | - |
perpendicular | first cooling | 960-700 | - | 0.0022 |
perpendicular | second heating | 840-990 | - | 0.0021 |
perpendicular | second cooling | 990-710 | - | 0.0021 |