Effects of the relative speed of a magnet moving to and from a single-domain YBCO bulks on their interaction force Original Research Article

Two single-domain YBCO bulks with different grain orientations were used to investigate the effect of relative moving speed between the magnet and YBCO bulk, on their interaction force at LN2 temperature under zero field cooling (ZFC) state. It is found that the levitation force of the sample S1 with c-axis perpendicular to the top surface is higher than that of the sample S2 with c-axis parallel to the top surface; the maximum levitation force (FML) is increasing with the increase of relative moving speed (VRMS) between the magnet and the samples at first and reaches a peak value for sample S1 and a peak zone values for sample S2, then the FML decreases with the increase of VRMS; the stiffness between the samples and the magnet is decreasing with the increase of the VRMS. This result is useful for the application of superconducting levitation.