Magnetic field distributions in a remanent state of screen-printed Ag-(Bi,Pb)2Sr2Ca2Cu3Ox tapes with different superconductor geometries
Magnetic field distributions in a remanent state of screen-printed Ag-(Bi,Pb)2Sr2Ca2Cu3Ox tapes with different superconductor geometries
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DOI：
10.1088/0953-2048/11/4/009
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发表时间：
1998-04-01
影响因子：
3.6
通讯作者：
Fujimoto, H
中科院分区：
文献类型：
--
作者：
Oota, A;Kawano, K;Fujimoto, H
本文制备了三种丝网印刷Ag-（Bi，Pb）（2）Sr_2Ca_2Cu_3 O_x超导带材，它们具有单一的矩形、方形和圆形超导芯，用扫描霍尔传感器磁测量法研究了去除垂直于带材表面的外场后的俘获磁场分布，有效面积为50 μ m × 50 μ m。通过模拟电流环进行的数值计算很好地解释了矩形带的测量磁分布，并且分析产生了150 A mm（-2）的临界电流密度J（c），其几乎与在77 K下从输运测量中发现的自场中的170 A mm（-2）的值一致。这为磁性剖面计算程序的有效性奠定了基础，并开辟了表征样品和确定J（c）值以代替传输测量的新途径。对于方形和圆形带，同样的计算结果与实验结果吻合得很好，其中传统的de四探针法不起作用，分析确定前者的J（c）值为60 A mm（-2），后者为40 A mm（-2），以代替输运数据。
Three kinds of screen-printed Ag-(Bi, Pb)(2)Sr2Ca2Cu3Ox tapes with a single rectangular, square and circular superconductor core have been fabricated, and the trapped magnetic field distributions after removal of external field perpendicular to a tape surface have been investigated using scanning Hall sensor magnetometry with an active area of 50 mu m x 50 mu m. Numerical calculations carried out by modelling current loops explain well the measured magnetic profile for the rectangular tape and the analyses yield a critical current density J(c) of 150 A mm(-2) that nearly agrees with the value of 170 A mm(-2) at 77 K in the self-field found from transport measurements. This establishes a basis for the validity of the calculation procedure for the magnetic profiles and opens a new way to characterize the sample and to determine the J(c) value in place of transport measurements. The same calculations give a nice agreement with the experimental profiles for the square and circular tapes, where the conventional de four-probe method does not work, and the analyses determine the J(c) value to be 60 A mm(-2) for the former and 40 A mm(-2) for the latter in place of the transport data.