Electrical and mechanical properties of (Bi,Pb)-2223 substituted by holmium

• Published in: Journal of advanced ceramics 2016-03, Vol.5 (1), p.54-69
• Main Authors: Abdeen, W., Marahba, S., Awad, R., Abou Aly, A. I., Ibrahim, I. H., Matar, M.
• Format: Article
• Language: English
• Subjects: Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Electrical resistivity; Glass; Materials Science; Mechanical properties; Nanotechnology; Natural Materials; Phase volume fraction; Plastic deformation; Research Article; Scanning electron microscopy; Structural Materials; Superconductivity; Vickers microhardness; Volt-ampere characteristics
• ISSN: 2226-4108; 2227-8508
• DOI: 10.1007/s40145-015-0173-x

The effect of the partial substitution of Ca 2+ by Ho 3+ ions on the electrical and mechanical properties of the superconducting phase (Bi,Pb)-2223 was studied. Superconducting samples of the type (Bi 1.8 Pb 0.4 )Sr 2 Ca 2.1− x Ho x Cu 3.1 O 10+δ were prepared by solid-state reaction technique under ambient pressure, and characterized by means of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The superconducting transition temperature T c and pseudogap temperature T * were estimated from electrical resistivity measurements, while the critical current density J c was determined from I–V curves. The electrical resistivity data were discussed according to bipolaron model in the absence of thermally excited individual polarons. The sample with x = 0.025 showed the highest phase volume fraction, T c , and J c . Room temperature Vickers microhardness measurements were carried out at different applied loads (0.25–5 N) in order to investigate the performance of the mechanical properties of (Bi 1.8 Pb 0.4 )Sr 2 Ca 2.1− x Ho x Cu 3.1 O 10+δ phase. It was found that all the samples exhibit normal indentation size effect (ISE). The Vickers microhardness number H V increased as x increased from 0 to 0.025. The experimental results were discussed in view of Meyer’s law, Hays–Kendall (HK) approach, elastic/plastic deformation (EPD) model, and proportional specimen resistance (PSR) model. The load independent (true) microhardness of (Bi 1.8 Pb 0.4 )Sr 2 Ca 2.1− x Ho x Cu 3.1 O 10+δ superconducting samples showed identical behavior to that of the PSR model.