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本文对比研究了超导材料磁测量中的SQUID法和Campbell法;并用高压PIT法制备的超导材料MgB2作为测量样品,用两种方法,测量了超导样品的临界电流密度,分别得到了样品的J_c-B关系曲线;SQUID法测量样品的外磁场可以达到6 T,此时材料已经处于失超状态,此方法测得的结果是样品各个小区域结果的平均值,SQUD还可以用来进一步标度材料的钉扎力行为,研究材料磁特性.Campbell法测量只能测量到外磁场强度为0.4 T,外磁场的交流部分的频率可以达到800 Hz,用这种测量方法得到的是整块样品的电流,由于测量计及材料内部微观结构缺陷等影响电流传输因素,所测结果小于直流磁化法,但更切近材料实际电流,能用来深入研究材料内部结构差别对材料电性能的影响.
In this paper, the SQUID method and Campbell method were compared in the magnetic measurement of superconducting materials. The superconducting material MgB2 prepared by high-pressure PIT method was used as the measurement sample. The critical current density of the superconducting sample was measured by two methods. The relationship between J_c-B curve and SQUID method is that the external magnetic field of the sample can reach 6 T, and the material has been in the state of quench. The result of this method is the average of the small area samples. SQUD can be used to further Scale material pinning force behavior, the magnetic properties of the material.Campbell method can only measure the measured magnetic field strength of 0.4 T, the external magnetic field of the AC part of the frequency can reach 800 Hz, with this measure is the whole block The current of the sample, which is influenced by the measurement of the microstructure of the material and the internal microstructure defects of the material, influences the current transmission. The measured result is smaller than that of the DC magnetization, but closer to the actual current of the material, which can be used to further study the influence of material internal structure differences on the electrical properties of the material.