【摘要】 高T_c氧化物 Bi_2-xPb_xSr₂Ca₂Cu₃O_y（x=0.2,0.3,0.4,0.5）大块超导体的 Meissner 效应表明存在110K 和85K 两个超导相,并且以110K 相为主,抗磁转变起始于103K 附近.不同样品在77.3K 的磁化实验表明,当 x≤0.3时,H_Cl≈28Oe,当 x>0.3时,H_cl=25Oe.x=0.3的样品在不同温度下的磁化实验结果表明,在 T=77.3—95K 之间,H_Cl与 T 成线性关系,且 dH_Cl/dT=-1.07Oe/K.两个超导相的存在导致磁化曲线峰的拉宽,且拉宽程度与85K 相所占的比例有关.更多还原

【Abstract】 Meissner effect measurements have shown that there are two superconducting phases,110 K phase and 85 K phase,in the high Tc oxide Bi2-xPbxSr2Ca2Cu3Oy bulk superconductors,that the volume fraction of 110 K phase is much larger than that of 85 K phase,and that the dia-inagnetic transitions begin at the temperature of about 103 K.The magnetization results of various samples at 77.3 K have shown that Hc1≈28Oe for the samples with x≤0.3 andHc1=25Oe for x>0.3.The magnetization results of the sample with x=0.3 in different temperatures show that there is linearity between Hc1 and T,and dHc1/dT=-1.07 Oe/K.The existence of the two superconducting phases makes the magnetization peak width,and the widening extent is dependent on the volume fraction of the 85 K phase.更多还原