Enhancement of the Electric Current in High- T c Superconductor Interacting with an Artificial Pinning Array
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ORIGINAL PAPER
Enhancement of the Electric Current in High-Tc Superconductor Interacting with an Artificial Pinning Array Le Thi Cam Tuyen1,2 · Phuoc Le Huu3 · Bui Duc Tinh4 Received: 27 March 2020 / Accepted: 25 September 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract The dynamics of the flux flow in the mixed state of high-Tc superconductor interacting with an artificial pinning array is considered. We calculate analytically the current density for the case of when the number of vortices outnumbers that of the pinning centers using the time-dependent Ginzburg-Landau equations in a magnetic field in the presence of strong thermal fluctuations. Our results show that the current density increases considerably with increasing pinning strength. It means that an original property of superconductor is recovered even in strong thermal fluctuations under a magnetic field by adding a pinning array to the mixed state of superconductor. Keywords High-Tc superconductor · Time-dependent Ginzburg-Landau equations · Artificial pinning array
1 Introduction Since the discovery of high-Tc superconductor, the effects of fluctuation and defect on superconductor have received much attention [1–4], due to both their practical and fundamental interest. The fluctuations in high-Tc superconductor were more pronounced than in the classical low-temperature superconductors because of short coherence lengths and high transition temperatures, but the degree of doping may also play a role [3, 4]. In fact, in high-Tc superconductor, there exist many specific defects which play an important role in superconductor. Free energy of a vortex line will lower if its core is located at a defect site, which Bui Duc Tinh
[email protected] Le Thi Cam Tuyen [email protected] 1
Ceramics and Biomaterials Research Group, Advanced Institute of Materials Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam
2
Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam
3
Department of Physics and Biophysics, Faculty of Basic Sciences, Can Tho University of Medicine and Pharmacy, 179 Nguyen Van Cu Street, Can Tho, Vietnam
4
Faculty of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Ha Noi, Vietnam
exists in the sample. Thus, strong pinning centers enhance the magnetic-flux pinning forces and a high current density [5–8]. Furthermore, in high-Tc superconductor, thermal fluctuations play an important role in leading to melting of the vortex lattice into a vortex liquid or changing of the efficiency of the disorder thermal depinning. In the past years, the study of pinned vortex matter in a superconducting film by well-defined artificial pinning arrays has advances by fabricating periodic arrays of pinning sites and this has been discussed [9–13]. There have been many interesting phenomena predicted by designing the pinning size, periodicity of the array, and array geometry [7, 8, 14]. Using the London theory, G. Mkrtchyan and V. Shmidt [15] analyzed the ma
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