| Records |
| Author |
Pahlke, P.; Sieger, M.; Ottolinger, R.; Lao, M.; Eisterer, M.; Meledin, A.; Van Tendeloo, G.; Haenisch, J.; Holzapfel, B.; Schultz, L.; Nielsch, K.; Huehne, R. |
| Title |
Influence of artificial pinning centers on structural and superconducting properties of thick YBCO films on ABAD-YSZ templates |
Type |
A1 Journal article |
| Year |
2018 |
Publication |
Superconductor science and technology |
Abbreviated Journal |
Supercond Sci Tech |
| Volume |
31 |
Issue |
4 |
Pages |
044007 |
Keywords  |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Recent efforts in the development of YBa2Cu3O7-x (YBCO) coated conductors are devoted to the increase of the critical current I-c in magnetic fields. This is typically realized by growing thicker YBCO layers as well as by the incorporation of artificial pinning centers. We studied the growth of doped YBCO layers with a thickness of up to 7 mu m using pulsed laser deposition with a growth rate of about 1.2 nm s(-1). Industrially fabricated ion-beam textured YSZ templates based on metal tapes were used as substrates for this study. The incorporation of BaHfO3 (BHO) or Ba2Y(Nb0.5Ta0.5)O-6 (BYNTO) secondary phase additions leads to a denser microstructure compared to undoped films. A purely c-axis-oriented YBCO growth is preserved up to a thickness of about 4 mu m, whereas misoriented texture components were observed in thicker films. The critical temperature is slightly reduced compared to undoped films and independent of film thickness. The critical current density J(c) of the BHO- and BYNTO-doped YBCO layers is lower at 77 K and self-field compared to pure YBCO layers; however, I-c increases up to a thickness of 5 mu m. A comparison between films with a thickness of 1.3 mu m revealed that the anisotropy of the critical current density J(c)(theta) strongly depends on the incorporated pinning centers. Whereas BHO nanorods lead to a strong B vertical bar vertical bar c-axis peak, the overall anisotropy is significantly reduced by the incorporation of BYNTO forming a mixture of short c-axis-oriented nanorods and small (a-b)-oriented platelets. As a result, the J(c) values of the doped films outperform the undoped samples at higher fields and lower temperatures for most magnetic field directions. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Bristol |
Editor |
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| Language |
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Wos |
000442196400001 |
Publication Date |
2018-02-15 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0953-2048 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.878 |
Times cited |
9 |
Open Access |
OpenAccess |
| Notes |
; The authors acknowledge financial support from EURO-TAPES, a collaborative project funded by the European Union's Seventh Framework Programme (FP7/ 2007-2013) under Grant Agreement no. 280432. We thank A Usoskin (Bruker HTS GmbH, Germany) for the provision of buffered templates, and M Bianchetti, A Kursumovic and J L Mac-Manus-Driscoll (University of Cambridge, UK) for the supply of BYNTO targets. The authors also gratefully acknowledge the technical assistance of J Scheiter, M Kuhnel, U Besold (IFW) and R Nast (KIT). ; |
Approved |
Most recent IF: 2.878 |
| Call Number |
UA @ lucian @ c:irua:153775 |
Serial |
5108 |
| Permanent link to this record |
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| Author |
Celentano, G.; Rizzo, F.; Augieri, A.; Mancini, A.; Pinto, V.; Rufoloni, A.; Vannozzi, A.; MacManus-Driscoll, J.L.; Feighan, J.; Kursumovic, A.; Meledin, A.; Mayer, J.; Van Tendeloo, G. |
| Title |
YBa2Cu3O7−xfilms with Ba2Y(Nb,Ta)O6nanoinclusions for high-field applications |
Type |
A1 Journal article |
| Year |
2020 |
Publication |
Superconductor Science & Technology |
Abbreviated Journal |
Supercond Sci Tech |
| Volume |
33 |
Issue |
4 |
Pages |
044010 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
The structural and transport properties of YBa2Cu3O7−x films grown by pulsed laser deposition with mixed 2.5 mol% Ba2YTaO6 (BYTO) and 2.5 mol% Ba2YNbO6 (BYNO) double-perovskite secondary phases are investigated in an extended film growth rate, R = 0.02–1.8 nm s−1. The effect of R on the film microstructure analyzed by TEM techniques shows an evolution from sparse and straight to denser, thinner and splayed continuous columns, with mixed BYNO + BYTO (BYNTO) composition, as R increases from 0.02 nm s−1 to 1.2 nm s−1. This microstructure results in very efficient flux pinning at 77 K, leading to a remarkable improvement in the critical current density (J c) behaviour, with the maximum pinning force density F p(Max) = 13.5 GN m−3 and the irreversibility field in excess of 11 T. In this range, the magnetic field values at which the F p is maximized varies from 1 T to 5 T, being related to the BYNTO columnar density. The film deposited when R = 0.3 nm s−1 exhibits the best performances over the whole temperature and magnetic field ranges, achieving F p(Max) = 900 GN m−3 at 10 K and 12 T. At higher rates, R > 1.2 nm s−1, BYNTO columns show a meandering nature and are prone to form short nanorods. In addition, in the YBCO film matrix a more disordered structure with a high density of short stacking faults is observed. From the analysis of the F p(H, T) curves it emerges that in films deposited at the high R limit, the vortex pinning is no longer dominated by BYNTO columnar defects, but by a new mechanism showing the typical temperature scaling law. Even though this microstructure produces a limited improvement at 77 K, it exhibits a strong J c improvement at lower temperature with F p = 700 GN m−3 at 10 K, 12 T and 900 GN m−3 at 4.2 K, 18 T. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Wos |
000525650500001 |
Publication Date |
2020-04-01 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0953-2048 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.6 |
Times cited |
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Open Access |
OpenAccess |
| Notes |
This work was partially financially supported by EUROTAPES, a collaborative project funded by the European Commission’s Seventh Framework Program (FP7/2007–2013) under Grant Agreement No. 280432. This work has been partially carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom programme 2014-2018 and 2019-2020 under grant agreement N° 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3 (Nano-engineered YBCO Superconducting Tapes for High Field Applications, NESTApp). G. C. acknowledges the support of Michele De Angelis for XRD measurements and calculations. |
Approved |
Most recent IF: 3.6; 2020 IF: 2.878 |
| Call Number |
UA @ lucian @c:irua:168582 |
Serial |
6394 |
| Permanent link to this record |
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| Author |
Molina, L.; Tan, H.; Biermans, E.; Batenburg, K.J.; Verbeeck, J.; Bals, S.; Van Tendeloo, G. |
| Title |
Barrier efficiency of sponge-like La2Zr2O7 buffer layers for YBCO-coated conductors |
Type |
A1 Journal article |
| Year |
2011 |
Publication |
Superconductor science and technology |
Abbreviated Journal |
Supercond Sci Tech |
| Volume |
24 |
Issue |
6 |
Pages |
065019-065019,8 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
| Abstract |
Solution derived La2Zr2O7 films have drawn much attention for potential applications as thermal barriers or low-cost buffer layers for coated conductor technology. Annealing and coating parameters strongly affect the microstructure of La2Zr2O7, but different film processing methods can yield similar microstructural features such as nanovoids and nanometer-sized La2Zr2O7 grains. Nanoporosity is a typical feature found in such films and the implications for the functionality of the films are investigated by a combination of scanning transmission electron microscopy (STEM), electron energy-loss spectroscopy (EELS) and quantitative electron tomography. Chemical solution based La2Zr2O7 films deposited on flexible Ni5 at.%W substrates with a {100}lang001rang biaxial texture were prepared for an in-depth characterization. A sponge-like structure composed of nanometer-sized voids is revealed by high-angle annular dark-field scanning transmission electron microscopy in combination with electron tomography. A three-dimensional quantification of nanovoids in the La2Zr2O7 film is obtained on a local scale. Mostly non-interconnected highly faceted nanovoids compromise more than one-fifth of the investigated sample volume. The diffusion barrier efficiency of a 170 nm thick La2Zr2O7 film is investigated by STEM-EELS, yielding a 1.8 ± 0.2 nm oxide layer beyond which no significant nickel diffusion can be detected and intermixing is observed. This is of particular significance for the functionality of YBa2Cu3O7 − δ coated conductor architectures based on solution derived La2Zr2O7 films as diffusion barriers. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
Bristol |
Editor |
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| Language |
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Wos |
000290472900021 |
Publication Date |
2011-04-20 |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0953-2048;1361-6668; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.878 |
Times cited |
31 |
Open Access |
|
| Notes |
Esteem 026019; Fwo |
Approved |
Most recent IF: 2.878; 2011 IF: 2.662 |
| Call Number |
UA @ lucian @ c:irua:88639UA @ admin @ c:irua:88639 |
Serial |
221 |
| Permanent link to this record |
