Perovskite-Type Metal Oxides Exhibiting Negligible Grain Boundary Resistance to Total Electrical Conductivity
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
In this paper, we report the synthesis, structure and electrical properties of the perovskite-type AZn<sub>0.33+<i>x</i></sub>Nb<sub>0.67−<i>x</i></sub>O<sub>3−δ</sub> (A = Sr or Ba; 0 ≤ <i>x</i> ≤ 0.08). The investigated compounds were prepared by employing the solid-state (ceramic) reaction using alkaline nitrates, zinc oxide, and niobium oxide at elevated temperatures in air. Powder X-ray diffraction (PXRD) showed the formation of disordered Zn and Nb at the B-sites of space group <i>Pm</i>3̅<i>m</i> with cubic structure and a lattice constant comparable to that of the literature. The AC impedance study showed mainly bulk contribution to the total electrical conductivity over the investigated frequency range of 0.01 Hz to 1 MHz in all the investigated atmospheres even at low temperatures, which is significantly different from that of the well-known perovskite-type B-site ordered BaCa<sub>0.33+<i>x</i></sub>Nb<sub>0.67−<i>x</i></sub>O<sub>3−δ</sub> and the disordered acceptor-doped BaCeO<sub>3</sub>. The bulk dielectric constant determined at 500 and 700 °C in air was found to be in the range of 35−100. In air, the isothermal bulk dielectric constant seems to increase with an increasing Zn content, and a similar trend was observed for total electrical conductivity. In dry and wet H<sub>2</sub>, the electrical conductivity decreases with an increasing Zn content in AZn<sub>0.33+<i>x</i></sub>Nb<sub>0.67−<i>x</i></sub>O<sub>3−δ</sub>, and the <i>x</i> = 0 member of the Ba compound exhibits the highest total conductivity of 7.2 × 10<sup>−3</sup> S cm<sup>−1</sup> in dry H<sub>2</sub> at 800 °C. Both Sr and Ba compounds were found to be stable against the reaction with pure CO<sub>2</sub> at 700 °C and H<sub>2</sub>O at 100 °C for a long period of time. SrZn<sub>0.33+<i>x</i></sub>Nb<sub>0.67−<i>x</i></sub>O<sub>3−δ</sub> was found to be stable in 30 ppm H<sub>2</sub>S at 800 °C, while the corresponding Ba compound formed reaction products such as BaS (JCPDS Card 01-0757), BaS<sub>2</sub> (JCPDS Card 21-0087), and BaS<sub>3</sub> (JCPDS Card 03-0824).
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.019 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it