Continuous Measurement on Electric-Field Versus Current-Density Characteristics of REBCO Coated Conductors in the Electric-Field Window From 10-2 Down to 10-11 V/m
Continuous Measurement on Electric-Field Versus Current-Density Characteristics of REBCO Coated Conductors in the Electric-Field Window From 10-2 Down to 10-11 V/m
复制标题
在 10-2 V/m 至 10-11 V/m 的电场窗口中连续测量 REBCO 涂层导体的电场与电流密度特性
DOI：
10.1109/tasc.2023.3258375
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发表时间：
2023
影响因子：
1.8
通讯作者：
Kiss Takanobu
中科院分区：
文献类型：
--
作者：
Wu Zeyu;Higashikawa Kohei;Kiss Takanobu
我们已经成功地测量了REBCO涂层导体的电场与电流密度（E-J）特性在外部磁场下的宽范围的电场窗口从10− 2下降到10− 11 V/m连续相结合的传输和磁化弛豫测量。高温超导体（HTS）可以覆盖AC和DC模式操作的应用的广泛方面，例如超导电机和持续模式MRI磁体。在这些应用中感应的电场根据工作频率的不同从10− 2到10− 11 V/m变化很大。这表明，相应的临界电流密度（Jc）也变化，由于圆化的E-J特性的高温超导体。也就是说，不可避免地要弄清宽电场范围内的E-J特性。通常，E-J特性通过电流传输法或磁化弛豫法测量。由于电压噪声的限制，标准输运测量通常可以覆盖从10− 2到大约10− 5到10−4V/m，而在DC磁化测量中，例如使用SQUID磁强计，测量期间的感应电场大约为10−8V/m或更小。在基于磁化弛豫的E-J特性测量中，我们采用霍尔探针磁显微镜来扩展电场窗口。我们开发了时间分辨率小于0.1 s的零维定点测量来测量磁化的初始衰减，这将电场窗口扩展到与输运测量相似的水平，即，大约10 - 5V/m。随后在10− 8至10− 11 V/m的电场范围内进行宽度方向的一维线扫描。此外，采用“焊剂退火”方法，以更短的测量时间获得约10− 11 V/m的电场范围。
We have succeeded in measuring electric-field versus current-density (E-J) characteristics of REBCO coated conductors under external magnetic field over wide-range electric-field window from 10−2down to 10−11V/m continuously by combining both transport- and magnetization-relaxation-measurements. High-temperature superconductors (HTSs) can cover broad aspects of applications for AC and DC mode operation such as superconducting motors and persistent-mode MRI magnets. Electric field induced in these applications vary significantly from 10−2down to 10−11V/m depending on the operating frequency. This indicates that the corresponding critical current density (Jc) also varies due to the roundedE-Jcharacteristics of HTS. Namely, it is inevitable to clarify theE-Jcharacteristics in wide range of electric fields. In general,E-Jcharacteristics are measured by current transport method or magnetization relaxation method. The standard transport measurement can cover typically from 10−2down to around 10−5to 10−4V/m because of the limit of voltage noise, whereas in a DC magnetization measurement such that using SQUID magnetometer for example, the induced electric field during the measurement is around 10−8V/m or less. In this study, we adopted Hall probe magnetic microscopy to expand the electric-field window in the measurements onE-Jcharacteristics based on magnetization relaxation. We developed zero-dimensional fixed-point measurement with a time resolution less than 0.1 s to measure the initial decay of the magnetization, which extends the electric-field window up to similar level to that of transport measurement, i.e., at around 10−5V/m. It was followed by a one-dimensional line scan in width-direction for the electric-field range between 10−8to 10−11V/m. Furthermore, “flux annealing” method was adopted to access the electric-field range around 10−11V/m with shorter measurement time.