Magnetic levitation force measurements for high Tc superconductors usually perform with the use of liquid nitrogen. It is both convenient and cheap. However, the temperature of the sample cannot be changed (77 K) and there is problem of frost. So, it is necessary to build another type of system to measure the levitation force of high Tc superconductor under different temperatures. In this study, we have transformed a close cycle cryogenic system (20–300 K), together with the use of an electronic balance, to measure the hysteretic curves of high Tc YBCO superconductor under different temperature. We also have used SQUID to measure the corresponding magnetization curves for our sample directly. From these results, we have found that the critical current density of our superconducting sample obtained from both measurements agree with each other as expected.
Journal of low temperature physics 131(3-4), pp.743-746