Magnetic Field Distribution and Levitation Force by Varying the External Field

We have measured the magnetic field and levitation force of bulk Y-Ba-Cu-O superconductors while the external field is controlled with a Bi-Sr-Ca-Cu-O superconducting magnet. The height dependence of the levitation force could be explained well in terms of the field gradient in the sample and radial component of the magnetic field. The field gradient also induced the trapped field and decreased the levitation force. The experiment data was different from the theoretical data as the magnetization process was repeated for levitated bulk superconductor.