Current–voltage (I–V) measurements were carried out for different current sweep rates (dI/dt) of transport current at zero magnetic field (H=0) and H≠0 in a polycrystalline sample of Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 3 O x (BSCCO) with a macroscopic cylindrical hole (CH) drilled. Similar measurements were also performed in the same BSCCO sample without CH for a comparison before drilling CH. For the same values of H, T, and dI/dt taken for both samples, it was observed that hysteresis effects appear in I–V curves upon cycling of transport current in upward and downward directions which contain the increasing and decreasing current values, respectively. However these effects which are seen in I–V curves of BSCCO sample with CH is more prominent than that of the BSCCO sample without CH. Further, the irreversibility effects in I–V curves of the BSCCO sample without CH disappears for H≠0 exhibiting nearly a linear behaviour, whereas the hysteretic behaviour in I–V curves of the BSCCO sample with CH is still observed. This interesting behaviour could be evaluated that macroscopic cylindrical hole improves pinning properties of sample acting as a macroscopic flux pinning center for flux lines.
