Naslov
Vortex pinning in CNT-doped MgB_2 superconductor

Autori
Babić, Emil ; Jerčinović, Marko ; Kim, J.H. ; Dou, X.

Izvornik
Journal of optoelectronics and advanced materials. Symposia (2066-057X) 1 (2009), 3; 455-458

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Superconductivity; MgB_2; Carbon nanotubes

Sažetak
The magnetoresistance and critical current density, J_c, of undoped and doped with short multiwalled carbon nanotubes (SMW-CNT) MgB_2 has been investigated in the temperature range 2 – 40K and in magnetic field B ≤ 16T. The samples were Fe – sheathed wires and tapes annealed at 900°C and 1000°C, respectively. Doping, by partial substitution of boron with carbon in MgB_2 , decreases the superconducting transition temperature Tc, but increases upper critical field H_c2 probably due to effects of alloying on two-gap MgB_2 superconductor. Simultaneously, inhomogeneous doping and nanoprecipitates formed during annealing enhance the pinning of vortices in doped samples. This shows up in enhanced pinning potential U_0(B), irreversibility field B_irr(T), J_c(B) and volume pinning force F_p = J_cB, especialy at elevated fields B. Unfortunately, the magnitude of J_c of present wires and tapes is limited by the core porosity (~50%) and an inhomogenous distribution of CNTs.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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