Scaling Behavior in Aluminum Doped MgB2 Superconductor

Magnetization measurements have been performed on Mg 1− x Al x B 2 (0≤ x ≤0.1) at various temperatures below T c and in fields up to 9 T. The reversible magnetization has been used to calculate the thermodynamic critical field ( H c ) which is then used to obtain a new universal behavior for both the critical current density ( J c ) and the pinning force ( P f ). This approach is based on vortex core energy ( ) and clearly exhibits the deviation from single vortex pinning with increasing temperature and higher concentration of Al-doping.