Fluxoid jump coupled high critical current density of nano-Co3O4 doped MgB2
IR@NPL: CSIR-National Physical Laboratory, New Delhi
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| Title |
Fluxoid jump coupled high critical current density of nano-Co3O4 doped MgB2
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| Creator |
Awana, V. P. S.
Isobe, M. Singh , K. P. Takayama-Muromachi, E. |
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| Subject |
Applied Physics/Condensed Matter
Physics |
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| Description |
Polycrystalline MgB2 samples, with added 0, 2, 4 and 6% nano-Co3O4, synthesized by vacuum ( 10(-5) Torr) annealing at 750 degrees C for two and a half hours each, are found to be nearly single phase with the presence of only a small quantity of Mg/MgO in the pristine sample in addition to the Co2O3 in the doped compounds. All the samples exhibited clear and sharp diamagnetic transitions at around 38 K, in zero-field-cooled (ZFC) magnetic susceptibility measurements with a sizeable signal. The field-cooled (FC) measurements, though having sharp transitions, showed a very small signal, indicating a high level of pinning centres in these samples. Further, some of the doped samples exhibited the paramagnetic Meissner effect (PME) in an applied field of 5 Oe. The critical current density (J(c)), estimated by invoking Bean's model for the pristine compound, increases by nearly an order of magnitude for 2% and 4% nano-Co3O4 doping and then decreases sharply for the 6% sample at nearly all studied temperatures and applied fields. Further, the increased Jc (similar to 10(8) A cm(-2)) is coupled with fluxoid jumps ( T <= 20 K and H <= 1 T). Fluxoid jumps are not seen in the relatively low Jc pristine or 6% sample. This means that the fluxoid jumps are intrinsic only to the high-J(c) samples.
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| Publisher |
Springer Verlag
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| Date |
2006-06
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://npl.csircentral.net/2481/1/68.pdf
Awana, V. P. S. and Isobe, M. and Singh , K. P. and Takayama-Muromachi, E. (2006) Fluxoid jump coupled high critical current density of nano-Co3O4 doped MgB2. Analog Integrated Circuits and Signal Processing , 19. pp. 551-555. ISSN 0925-1030 |
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| Relation |
http://npl.csircentral.net/2481/
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