论文部分内容阅读
电阻和交流磁化率测量表明在热处理过程中浇铸退火样品的冷却速率对Bi-Pb-Sr-Ca-Cu-O材料中的110K超导相有一定影响。样品从845℃在室温空气中淬火引起了晶格中的氧缺位,导致了沿c轴方向晶胞尺寸的轻微变化。直流磁化和比热反常ΔC测量指出快速冷却能缩减高温相的转变温度和下临界场,并减弱了对磁通线钉扎力。名义组分为Bi_(1·7)Pb_(0·5)Sr_2Ca_2Cu_(4·5)O_y的样品,比热反常峰值和YBa_2Cu_3O_7比较仍然较小。由直流磁化曲线估算出样品中超导体积所占的比例为20%左右。
Resistance and AC susceptibility measurements show that the cooling rate of cast annealed samples during heat treatment has some effect on the 110K superconducting phase in the Bi-Pb-Sr-Ca-Cu-O material. Quenching the sample from 845 ° C in air at room temperature caused an oxygen vacancy in the crystal lattice, resulting in a slight change in cell size along the c-axis. DC magnetization and specific heat ΔC measurements indicate that rapid cooling can reduce the transition temperature and lower critical field of the high temperature phase and weaken the pinning force on the flux line. The samples with the nominal composition of Bi_ (1.7) Pb_ (0.5) Sr_2Ca_2Cu_ (4.5) O_y are still smaller than the peaks of thermal anomalies and YBa_2Cu_3O_7. The DC magnetization curve estimates the proportion of superconducting volume in the sample is about 20%.