A Comparative Study of Ge-Based Organometallic Additions to MgB2
| Autor: | Dan Batalu, A. Ionescu, Takashi Nakamura, Petre Badica, Stelian Popa, Iuliana Pasuk, Gheorghe Aldica, Monica Enculescu |
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| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | IEEE Transactions on Applied Superconductivity. 28:1-5 |
| ISSN: | 1558-2515 1051-8223 |
| DOI: | 10.1109/tasc.2018.2808366 |
| Popis: | Four Ge-based organometallic (OM = C 6 H 10 Ge 2 O 7 ) polymers with similar chemical composition were used as additions for MgB 2 . MgB 2 (OM) 0.0014 dense samples with a relative density higher than 97% were obtained by ex situ spark plasma sintering. The critical current density and the irreversibility magnetic field of the added samples are slightly improved at high magnetic fields by repagermanium (Alfa Aesar) addition when compared to the pristine reference sample. Addition of Ge-straight-chain polymer shows some improvement of the maximum volume pinning force, Fp max . There is no significant Ge substitution in the crystal lattice of MgB 2 , while C substitutes for B. Pinning mechanism is mainly of a point pinning type, with the grain boundary pinning mechanism strengthening at lower temperatures and when additives are not used. A relatively high amount of carbon in the samples washes out the Ge effects on pinning-force-related parameters. The structure and morphology of the polymer additive play an important role in dispersion when mixing, impacting the quality of the superconducting properties. The nanosize dimension of the pristine MgB 2 powder shows also some drawbacks in mixing and sintering. |
| Databáze: | OpenAIRE |
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