Prominent bulk pinning effect in the (formula presented) superconductor

We report the magnetic-field dependence of the irreversible magnetization of the recently discovered binary superconductor (formula presented) For the temperature region of (formula presented) the contribution of the bulk pinning to the magnetization overwhelms that of the surface pinning. This was evident from the fact that the magnetization curves (formula presented) were well described by the critical-state model without considering the reversible magnetization and the surface-pinning effect. It was also found that the (formula presented) curves at various temperatures scaled when the field and the magnetization were normalized by the characteristic scaling factors (formula presented) and (formula presented) respectively. This feature suggests that the pinning mechanism determining the hysteresis in (formula presented) is unique below (formula presented)