Influence of BaZrO3 dopant concentration on properties of YBa2Cu3O6+x films in magnetic fields up to 30 T (original) (raw)
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Scientific Reports, 2019
Striving to improve the critical current density Jc of superconducting YBa2Cu3O6+x (YBCO) thin films via enhanced vortex pinning, the interplay between film growth mechanisms and the formation of nanosized defects, both natural and artificial, is systematically studied in undoped and BaZrO3 (BZO)-doped YBCO thin films. The films were grown via pulsed laser deposition (PLD), varying the crystal grain size of the targets in addition to the dopant content. The microstructure of the PLD target has been observed to have a great impact on that of the deposited thin films, including the formation of vortex pinning centers, which has direct implications on the superconducting performance, especially on the isotropy of flux pinning properties. Based on experimentally measured angular dependencies of Jc, coupled with a molecular dynamics (MD) simulation of flux pinning in the YBCO films, we present a quantitative model of how the splay and fragmentation of BZO nanorods artifically introduced ...
Enhanced superconducting properties of YBa2Cu3O7−δ thin film with magnetic nanolayer additions
Ceramics International, 2016
Vertically aligned nanocomposite (VAN) (La 0.7 Sr 0.3 MnO 3) 0.5 (CeO 2) 0.5 and pure La 0.7 Sr 0.3 MnO 3 layers were incorporated into YBa 2 Cu 3 O 7-δ (YBCO) thin films as bilayer stacks for magnetic flux pinning enhancement. The films show high epitaxial quality, suggested by XRD and TEM study. The critical temperature T c of the bilayers is about 90 K, which is close to that of pure YBCO films, while both the self-field J c sf and in-field critical current density J c in-field are largely enhanced. Among all samples, the film with VAN cap layer shows the highest J c values in all field ranges. This study demonstrates an effective way towards the tunable pinning effect for YBCO coated conductors by both defect and magnetic pinning.
Strong isotropic flux pinning in solution-derived YBa2Cu3O7−x nanocomposite superconductor films
Nature Materials, 2007
Power applications of superconductors will be tremendously boosted if an effective method for magnetic flux immobilization is discovered. Here, we report the most efficient vortex-pinning mechanism reported so far which, in addition, is based on a low-cost chemical solution deposition technique. A dense array of defects in the superconducting matrix is induced in YBa 2 Cu 3 O 7−x −BaZrO 3 nanocomposites where BaZrO 3 nanodots are randomly oriented. Non-coherent interfaces are the driving force for generating a new type of nanostructured superconductor. Angle-dependent critical-current measurements demonstrate that a strong and isotropic flux-pinning mechanism is extremely effective at high temperatures and high magnetic fields leading to high-temperature superconductors with record values of pinning force. The maximum vortex-pinning force achieved at 65 K, 78 GN m −3 , is 500% higher than that of the best low-temperature NbTi superconductors at 4.2 K and so a great wealth of high-field applications will be possible at high temperatures.
Magnetization and Susceptibility Studies on BaZrO 3 -Doped YBa 2 Cu 3 O 7 − x Bulk Superconductors
Journal of Superconductivity, 2002
We studied the YBa2Cu3O7 - x bulk superconductor doped with BaZrO3 up to 50 wt.%, obtained by solid-state reaction powder technology. From DC magnetization loops and low frequency AC susceptibility measurements we determined the influence of the BaZrO3 doping level on the critical temperature, critical current density, field for full penetration, and intergrain lower critical field. The results show that
Flux pinning in YBa2Cu3O7 thin films grown by d.c. magnetron sputtering
Cryogenics, 1992
Thin films of YBa2Cu307 (YBCO) were deposited on single crystalline LaAIO 3 substrates using d.c. magnetron sputtering. The quality of the films has been assessed by X-ray diffraction; YBa2Cu307 grows epitaxially with the c-axis parallel to the substrate normal. For some choices of the deposition parameters in the sputtering process, it was found that secondary phases were precipitated in the films. By a deliberate choice of deposition parameters, semi-coherently grown Y203 (yttria) inclusions could be obtained. They had square platelet or cubical shapes with sizes from 5-20 nm and thickness -10 nm. The superconducting properties of the YBa2Cu307 films were investigated using SQUID magnetometry. Magnetization measurements on films with different densities of semicoherent Y203 inclusions indicate an enhanced flux pinning capability with increasing inclusion density.
IOP conference series, 2017
View the article online for updates and enhancements. Related content Viewpoint on fast track communication by V Selvamanickam et al: Critical current density above 15 MA cm2 at 30 K, 3 T in 2.2 m thick heavily-doped (Gd,Y)Ba2Cu3Ox superconductor tapes Timothy Haugan-Effect of ZnO and Zn 0,95 Mn 0,05 O nanoparticle inclusions on YBCO polycrystalline pinning properties M Annabi, I Bouchoucha, F Ben Azzouz et al.-Flux pinning enhancement in YBa2Cu3O7-x films with BaSnO3 nanoparticles Chakrapani V Varanasi, P N Barnes, J Burke et al.
YBa2Cu3O x superconducting thin films prepared by low temperature vacuum codeposition
Bulletin of Materials Science, 1991
Y-Ba-Cu-O films were prepared by low temperature codeposition of three components. The Y and Cu contents were evaporated from metallic sources, while Ba was vacuum-evaporated from Ba, BaO and BaF 2 sources in separate codeposition experiments. The lowest temperature at which superconducting YBa2Cu30 x thin films (about 0.5 pm thick) prepared in situ was near 500°C. This process enables preparation of superconducting films on various substrates (SrTiO~, MgO, AI20 3, Si) without a buffer layer. Zero-resistance critical temperature was as high as 88 K and the critical current density was 104A/cm 2 at 4.2 K. The morphology of the films was granular with disordered grain orientation, the average grain size being typically 0.5 pm.
Enhanced Flux Pinning Properties of YBCO Thin Films With Various Pinning Landscapes
IEEE Transactions on Applied Superconductivity, 2017
Pinning enhancement for YBa 2 Cu 3 O 7 −δ (YBCO) thin films is critical for their future applications such as superconducting cables, generators, and motors. In this study, several pinning landscapes are introduced and compared for improving the superconducting properties of YBCO thin films. First, BaZrO 3 (BZO) nanoparticles have been doped into YBCO matrix providing uniform defect pinning centers and resulting in the superconducting property enhancement. Second, a magnetic nanocomposite of (La 0 .7 Sr 0 .3 MnO 3 (LSMO)) x (CeO 2) 1 −x (with compositions of LSMO and CeO 2 varied from 50:50 to 70:30) has been incorporated into YBCO as either a cap layer or a buffer layer. Using this approach, both magnetic pinning and defects pinning are introduced in the systems. Third, multilayers of (LSMO) 0 .5 (CeO 2) 0 .5 /YBCO have been deposited to achieve uniform defect and magnetic pinning effects through the film thickness. The superconducting properties (critical temperature T c , and especially the critical current density J c) are compared for all the YBCO films with different pinning landscapes, and the corresponding pinning mechanisms are also discussed for each case. It is found that the pinning effect of YBCO film with magnetic nanocomposite layer is more significant under lower applied field, compared to the BZO-YBCO film. Through this comparison study, optimum pinning landscapes with combined defects and magnetic pinning approaches are proposed.
IEEE Transactions on Applied Superconductivity, 2018
This study investigates chemically decorated surfaces as tools for the improvement of transport properties in superconducting YBa 2 Cu 3 O 7-x films. This approach, still to be thoroughly investigated, makes use of low-cost, easily-tunable chemical methods to obtain self-assembled oxide nanostructures on a substrate that will serve, in a second step, for the deposition of the superconducting film itself. The structures are supposed to produce in the superconducting matrix a specific amount of strain which is generally held responsible for the increased transport capacity of variously doped samples. For the growth of the nanostructures two different methods have been employed: Polymer Assisted Deposition (PAD) and Metal Organic Decomposition (MOD). The main advantages and disadvantages of these two routes are discussed. The oxide chosen for the deposition is one commonly used for artificial pinning in YBa 2 Cu 3 O 7-x , namely, Ba 2 YNbO 6 , together with the less common but highly interesting ferromagnetic compound La 0,77 Sr 0,33 MnO 3. We also show how the density of these nanostructures can be easily controlled and the necessary requirements for the growth of nanostructures are determined. A variety of crystalline substrates were tested for the deposition of the nanoparticles, such as SrTiO 3 , YSZ, MgO. YBa 2 Cu 3 O 7-x films have been deposited on selected samples via standard low-fluorine Metal Organic Decomposition and characterized SEM, XRD, VSM, DC resistivity and critical current measurements. The presence of the nanostructures results, in this case, in a slight increased value of J c which can be ascribed to the relatively low density of nanoparticles.