Mapping Dynamical Magnetic Responses of Ultrathin Micron-Size Superconducting Films Using Nitrogen-Vacancy Centers in Diamond
Mapping Dynamical Magnetic Responses of Ultrathin Micron-Size Superconducting Films Using Nitrogen-Vacancy Centers in Diamond
复制标题
使用金刚石中的氮空位中心绘制超薄微米级超导薄膜的动态磁响应
DOI：
10.1021/acs.nanolett.9b02298
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发表时间：
2019
期刊：
影响因子：
10.8
通讯作者：
Tiang Chuanshan
中科院分区：
文献类型：
--
作者：
Xu Ying;Yu Yijun;Hui Yuen Yung;Su Yudan;Cheng Jun;Chang Huan-Cheng;Zhang Yuanbo;Shen Y. Ron;Tiang Chuanshan
二维超导体因其科学新颖性、结构可调性和有用的性质而引起了人们越来越多的兴趣。然而，对它们的磁性响应的研究往往因为难以生长高质量和均匀的大尺寸样品而受到阻碍。我们报道了一种利用金刚石中的NV中心作为传感器的成像方法，该传感器能够绘制出微米尺寸的超薄超导薄膜上的微波磁场分布。对33 nm厚的Bi2Sr2CaCu2O8+δ薄膜和125 nm厚的块状薄膜的测量表明，交流迈斯纳效应(或交流磁场的斥力)分别出现在78K和91K，后者是两种薄膜的超导转变温度。薄膜的反常交流磁响应可能是由于薄膜中的热激励涡旋-反涡旋扩散运动所致。我们的交流磁强计的空间分辨率受到光学衍射的限制，噪声水平为14μT/Hz1/2。该技术可以扩展到更高的探测灵敏度，以提取超薄或单层超导样品的局部交流电导率/磁化率，以及其他横向尺寸有限的二维奇异薄膜的交流磁响应。
Two-dimensional superconductors have attracted growing interest because of their scientific novelty, structural tunability, and useful properties. Studies of their magnetic responses, however, are often hampered by difficulties to grow large-size samples of high quality and uniformity. We report here an imaging method that employed NV–centers in diamond as a sensor capable of mapping out the microwave magnetic field distribution on an ultrathin superconducting film of micron size. Measurements on a 33 nm thick film and a 125 nm thick bulklike film of Bi2Sr2CaCu2O8+δrevealed that the alternating current (ac) Meissner effect (or repulsion of ac magnetic field) set in at 78 and 91 K, respectively; the latter was the superconducting transition temperature of both films. The unusual ac magnetic response of the thin film presumably was due to thermally excited vortex–antivortex diffusive motion in the film. Spatial resolution of our ac magnetometer was limited by optical diffraction and the noise level was at 14 μT/Hz1/2. The technique could be extended with better detection sensitivity to extract local ac conductivity/susceptibility of ultrathin or monolayer superconducting samples as well as ac magnetic responses of other two-dimensional exotic thin films of limited lateral size.