| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1618021 | Journal of Alloys and Compounds | 2010 | 4 Pages |
We have studied the electrical resistivity, magnetoresistance (MR), and specific heat of (1 − x) Pr0.67Ba0.33MnO3:xAg2O (x = 0–30 mol% Ag2O) composite manganites. Two insulator–metal-like transitions (TP1 ∼ 194 K and TP2 ∼ 160 K) are observed in the electrical resistivity behaviour of the pristine material Pr0.67Ba0.33MnO3 (PBMO). With Ag2O addition, TP1 becomes sharper whereas TP2 disappears beyond 25 mol% Ag2O addition. Electrical resistivity also decreases in the composites in the whole temperature range of measurement. Intrinsic MR (due to grain) gets enhanced from 22% for the pure sample to ∼40% for 30% Ag2O sample with 0.6 T field. Extrinsic MR (due to grain boundary), however, is found to decrease with Ag2O addition. Peak MR enhances in composite at the same temperature and at low temperature, beyond the peak, it is almost constant in a large temperature window. Anomaly observed in the specific heat (CP) near the high temperature insulator–metal transition temperature for various samples signifies the onset of magnetic ordering. Also CP vs T trend is similar in all the samples indicating that Ag2O addition does not produce any magnetic inhomogeneity.
Research highlights▶ In the present manuscript we discuss about the electrical resistivity, magnetoresistance (MR), and specific heat of (1 − x) Pr0.67Ba0.33MnO3:xAg2O (x = 0–30 mol% Ag2O) composite manganites. ▶ Two insulator–metal-like transitions (TP1 ∼ 194 K and TP2 ∼ 160 K) are observed in the electrical resistivity behaviour of the pristine material Pr0.67Ba0.33MnO3 (PBMO). ▶ With Ag2O addition, TP1 becomes sharper whereas TP2 disappears beyond 25 mol% Ag2O addition. Intrinsic MR (due to grain) gets enhanced from 22% for the pure sample to ∼40% for 30% Ag2O sample with 0.6 T field. ▶ Extrinsic MR (due to grain boundary), however, is found to decrease with Ag2O addition. ▶ Anomaly observed in the specific heat (CP) near the high temperature insulator–metal transition temperature for various samples signifies the onset of magnetic ordering and the specific heat trend is similar in all the samples which signifies that Ag2O addition does not produce any magnetic inhomogeneity.
