Angular dependence of magnetization in high-T/sub c/ Bi/sub 1.6/Pb/sub 0.4/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub y/ superconductor

The angular dependence of magnetization in the Bi/sub 1.6/Pb/sub 0.4/Sr/sub 2/CaCu/sub 3/O/sub y/ high-T/sub c/ superconductor was measured by rotating the sample relative to the external magnetic field. At T=80 K, pinned fluxoids rigidly rotate with the sample and this feature is reflected by the cosine function of magnetization curve with slight deviation in relatively low external magnetic field. The concept of fluxoid dispersion was introduced, and the angular dependence of magnetization in high-T/sub c/ superconductor was quantitatively interpreted.<>