Normalized zero field cooling magnetization as a function of temperature for all samples of Table I. The inset shows onset vs the actual C content as determined by -axis lattice parameter.
Upper critical field vs from transport experiments (symbols), where (Ref. 29) and was defined at the onset of the curves for all samples. Dashed lines correspond to fits using Eq. (1) in Ref. 11. The inset shows the dependence of extrapolated to , normalized and with (dotted lines are guides to the eyes).
(a) field dependence obtained from magnetization loops for all samples described in Table I at (solid symbols) and (open symbols). (b) as a function of the applied field of all four samples at . The inset shows the same normalized as a function of the reduced field where the criterion for is . The full line is the theoretical field dependence of proposed for the grain boundary flux pinning.
Bright-field images of the (a) SiC and (b) swCNT samples showing the characteristic grain sizes and precipitates of doped . The insets show selected area diffraction patterns indicative of polycrystalline structure in both samples, where diffraction rings from the amorphous or secondary phases appear only in the inset (a).
Nominal composition, synthesis temperature , lattice parameters, actual C content calculated from -axis values, and as determined from the onset of the superconducting transition.
Reduced temperature , residual resistivity ratio , and parameters and obtained by fitting curves with Eq. (1) of Ref. 11 (for complete explanation see Refs. 7 and 8).
Article metrics loading...
Full text loading...