Experimental observation of a crossing in the force–displacement hysteretic curve of a melt processed YBaCuO bulk superconductor

An experimental observation is presented a crossing in the force–displacement hysteretic curve of a melt processed high-temperature superconductor (HTS) with high critical current density. The causes of the crossing were listed and discussed. In addition, the influence of the speed of the permanent magnet (PM) on the maximum levitation force was measured in this work. It was found that both with and without the crossing in the hysteretic curve, with the increase of the moving speed of the PM, the maximum levitation force of the HTS with high critical current density decreases gradually. We interpret these results by analyzing the power dissipation in the HTS when the PM moved above the superconductor.