Effects of Al doping on the superconducting and structural properties of MgB2

Flux pinning force in bulkMgB2with variable grain size

“…The peak of the f p curves takes place at b peak ϳ 0.2 for all samples, which seems to be intrinsic to bulk MgB 2 . This position of the peak has been observed in MgB 2 in many other works [13][14][15][16][17] and also in some LTSs, such as the A-15 Nb 3 Sn ͑Refs. 18-20͒ and the Chevrel-phase PbMo 6 S 8 , 21 characterized by F p ϰ b 1/2 ͑1−b͒ 2 .…”

Enhancement of critical current density in low level Al-doped MgB2

“…Nevertheless, our results compare favourably with previous studies of low level Al doped (~5 at.%) samples, where the doping caused sharp reductions of J c over the temperature range 5 -35 K [9,15]. Most importantly, the possibility now exists to tune the intraband scattering rates by selectively doping both the B and Mg sites.…”

“…Extensive research into substitutional chemistry has shown that only a few elements can substitute onto the Mg site [8] (Al [8][9][10][11][12], Li [13], Cu [14]). However, so far, there have been no reports of improved superconducting properties with doping on the Mg site [11,15,16]. It is possible that the doping levels studied have been too high or that poor microstructures have obscured any improved properties.…”

Exploring the Superconductors with Scanning Electron Microscopy (SEM)

“…For most of the practical applications, high critical current density (J c ) in the presence of a magnetic field along with high upper critical field (H C2 ) and high irreversibility field (H irr ) are required. Moderate impurities and nano (n) materials are being used to improve these parameters [7][8][9][10][11][12][13][14]. In particular, significant flux pinning enhancement in MgB 2 is observed with n-SiC addition [15].…”