Naslov
Flux pinning and critical currents in polycrystalline MgB_2

Autori
Kušević, Ivica ; Marohnić, Željko ; Babić, Emil ; Drobac, Đuro ; Wang, X.L. ; Dou, Shi Xue

Izvornik
Solid State Communications (0038-1098) 122 (2002), 6; 347-350

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

Ključne riječi
flux pinning; critical currents; MgB_2

Sažetak
The results of accurate electrical resistivity and ac susceptibility measurements for a well-characterized, single phase MgB2 sample are reported. The onset of electrical resistivity in magnetic fields B less than or equal to I T is thermally activated R exp(-U(T, B)/k(B)T) with U-0(B) = U(T = 0, B) infinity 1/rootB for B greater than or equal to 0.2T. The pinning potential U-0(B less than or equal to I T) is similar to that for YBa2Cu3O7 compound, but the region of flux liquid is quite narrow and the uppercritical field Bc(2) fairly low. High-resolution ac susceptibility measurements show homogeneous superconducting behavior (no Josephson coupled grains) and yield true zerofield critical cur-rent density J(c) similar to (1 - T/T-c)(n) with n approximate to 1.2. The comparison of literature results for J(c) with our ones shows pronounced mass density dependence of J(c) in bulk untextured MgB2 samples.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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