期刊
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
卷 21, 期 9, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0953-2048/21/9/092004
关键词
-
资金
- Engineering and Physical Sciences Research Council [EP/F016271/1] Funding Source: researchfish
- EPSRC [EP/F016271/1] Funding Source: UKRI
Here we report the use of global and local magnetometry and Hall probe imaging to investigate the electromagnetic connectivity of the superconducting current path in the oxygen-deficient fluorine-free Nd-based oxypnictides. High resolution transmission electron microscopy and scanning electron microscopy show strongly layered crystallites, evidence for a similar to 5 nm amorphous oxide around individual particles, and second phase neodymium oxide which may contribute to the large paramagnetic background at high field and at high temperatures. From global magnetometry and electrical transport measurements it is clear that there is a small supercurrent flowing on macroscopic sample dimensions (mm), with a lower bound for the average (over this length scale) critical current density of the order of 10(3) A cm(-2). From magnetometry of powder samples and local Hall probe imaging of a single large conglomerate particle similar to 120 mu m it is clear that, on smaller scales, there is better current connectivity with a critical current density of the order of 5 x 10(4) A cm(-2). We find enhanced flux creep around the second peak anomaly in the magnetization curve and an irreversibility line significantly below H(c2)(T) as determined by ac calorimetry.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据