Pinning Potential and Critical Current Densities in Powder Melting Processed Y(Ho)BCO Samples

Magnetic relaxation and magnetization of the powder melting Y_1-xHo_xBa₂Cu₃O₇ (x =0.2, 0.4 and 0.6) samples have been measured at the temperature of 70K. The pinning potential U and magnetization critical current density J_c have been obtained according to the Anderson-Kim model and Bean model. It is found that both U and J_c were influenced by doping Ho. In the sample with x = 0.4 the pinning potential U has a Value of 3.2eV when the field is equal to 1 kG and parallel to c-axis, which is the highest one we have known in the high T_c superconductors.