Effects of Cobalt Doping on In-field
Critical Current Density in YBa2Cu3O7-x
Most likely, the cobalt atoms in the lattice, because of their difference in size, are serving as localized point defects for flux-pinning sites, which apparently become even more effective as the temperature decreases.
Data taken with our first YBa2Cu3O7-x sample.
Type of Scale Used on Graph
Temperature at Which Data was Taken
65K
77K
Typical Scale:

Critical Current Density (Jc) measured in Amps/cm2 Versus Magnetic Field measured in Gauss.
Log Scale:

The same data is plotted on a logarithmic scale so that differences are easier to locate.
Normalized Scale:

Values of Jc(B) are divided by Jc(0) so that the effect on field dependence can be seen clearly.
Resistivity as a Function of Temperature for the Various Doping Levels of Cobalt