Superconductive REBCO Thin Films and Their Nanocomposites: The Role of Rare-Earth Oxides in Promoting Sustainable Energy

Abstract

The lossless transmission of direct electrical currents in superconductors is very often regarded as an "energy superhighway" with greatly enhanced efficiency. With the discovery of high temperature superconductors (HTS) in the late eighties, the prospect of using these materials in efficient and advanced technological applications became very prominent. The elevated operating temperatures as compared to low temperature superconductors (LTS), relaxing cooling requirements, and the gradual development of facile synthesis processes raised hopes for a broad breakthrough of superconductor technology. The impact of superconductor technology on the economy and energy sectors is predicted to be huge if these are utilized on a large scale. The development of superconducting tapes with high critical current density (J c) is crucial for their use in transmission cables. Many countries these days are running projects to develop wires from these HTS materials and simultaneously field trials are being conducted to assess the feasibility of this technology. These HTS wires can carry electrical currents more than 100 times larger than their conventional counterparts with minimal loss of energy. The increased efficiency of HTS electric power products may result in greatly reduced carbon emissions compared to those resulting from using the conventional alternatives. In order to use the thin films of YBa 2 Cu 3 O 7−δ (YBCO) and REBCO [RE (rare-earth) = Sm, Gd, Eu etc.], members of the HTS family, for future technological applications, the enhancement of J c over wide range of temperatures and applied magnetic fields is highly desired. The enhancement of J c of YBCO and REBCO films has been successfully demonstrated by employing different techniques which include doping by rare-earth atoms, incorporating nanoscale secondary phase inclusions into the REBCO film matrix, decoration of the substrate surface etc. which generate artificial pinning centers (APCs). In this review, the development of the materials engineering aspect that has been conducted over the last two decades to improve the current carrying capability of HTS thin films is presented. The effect of controlled incorporation of APCs through various methods and techniques on the superconducting properties of YBCO and REBCO thin films is presented, heading toward superior performance of such superconducting thin films.

Superfluid density from magnetic penetration depth measurements in Nb–Cu 3D nano-composite films

“…2 b). We attribute the two peaks with the intra and inter-granular losses for granular superconductors in line with the observations and discussions related to high T c Cuprate superconducting thin films 32 – 34 . The peak at higher temperatures, T ph (close to T c or the temperature where the diamagnetic shielding response develops in the films) can be associated with the increase in dissipation due to the movement of intra-granular vortices within the superconducting Nb grains.…”

Ferromagnetism and Superconductivity in CaRuO3/YBa2Cu3O7-δ Heterostructures

“…To fulfil this criterion, vortices in the material have to be strongly pinned. Many possibilities to inhibit vortex motion have been found that led to an increase of the superconducting critical current density, J c [ 6 ]. Some of the methods developed to introduce natural and artificial pinning centers are: microstructural variations [ 7 , 8 ], creation of oxygen vacancies [ 9 ], the addition of secondary phases [ 10 , 11 ], magnetic nanoparticles, or nanolayers [ 12 , 13 , 14 , 15 ].…”

Combinatorial Screening of Cuprate Superconductors by Drop-On-Demand Inkjet Printing

“…1−4 Superconducting REBa 2 Cu 3 O 7 (REBCO, RE = rare earth) films and coated conductors (CC) possess an inherent advantage due to the high performances in a significantly broad spectrum of the magnetic field−temperature (B−T) diagram, hence showing promising properties for wide market implementation. 5 Due to historical reasons, YBCO has been the most investigated REBCO superconductor. 6 Nevertheless, a wide range of RE ions that can replace Y are driving the current research interest.…”