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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. pdf  url
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  Title Influence of artificial pinning centers on structural and superconducting properties of thick YBCO films on ABAD-YSZ templates Type A1 Journal article
  Year (down) 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  
  Corporate Author Thesis  
  Publisher Place of Publication Bristol Editor  
  Language Wos 000442196400001 Publication Date 2018-02-15  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0953-2048 ISBN 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  
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Author Sieger, M.; Pahlke, P.; Lao, M.; Eisterer, M.; Meledin, A.; Van Tendeloo, G.; Ottolinger, R.; Haenisch, J.; Holzapfel, B.; Usoskin, A.; Kursumovic, A.; MacManus-Driscoll, J.L.; Stafford, B.H.; Bauer, M.; Nielsch, K.; Schultz, L.; Huehne, R. url  doi
openurl 
  Title Tailoring microstructure and superconducting properties in thick BaHfO3 and Ba2YNb/Ta)O-6 doped YBCO films on technical templates Type A1 Journal article
  Year (down) 2017 Publication IEEE transactions on applied superconductivity Abbreviated Journal  
  Volume 27 Issue 4 Pages 6601407  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The current transport capability of YBa2Cu3O7-x(YBCO) based coated conductors (CCs) is mainly limited by two features: the grain boundaries of the used textured template, which are transferred into the superconducting film through the buffer layers, and the ability to pin magnetic flux lines by incorporation of defined defects in the crystal lattice. By adjusting the deposition conditions, it is possible to tailor the pinning landscape in doped YBCO in order to meet specific working conditions (T, B) for CC applications. To study these effects, we deposited YBCO layers with a thickness of about 1-2 mu m using pulsed laser deposition on buffered rolling-assisted biaxially textured Ni-W substrates as well as on metal tapes having either an ion-beam-texturedYSZbuffer or an MgO layer textured by inclined substrate deposition. BaHfO3 and the mixed double-perovskite Ba2Y(Nb/Ta)O-6 were incorporated as artificial pinning centers in these YBCO layers. X-ray diffraction confirmed the epitaxial growth of the superconductor on these templates as well as the biaxially oriented incorporation of the secondary phase additions in the YBCO matrix. A critical current density J(c) of more than 2 MA/cm(2) was achieved at 77 K in self-field for 1-2 mu m thick films. Detailed TEM (transmission electron microscopy) studies revealed that the structure of the secondary phase can be tuned, forming c-axis aligned nanocolumns, ab-oriented platelets, or a combination of both. Transport measurements show that the J(c) anisotropy in magnetic fields is reduced by doping and the peak in the J(c) (theta) curves can be correlated to the microstructural features.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication New York, N.Y. Editor  
  Language Wos 000394588100001 Publication Date 2016-12-24  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1051-8223 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 12 Open Access OpenAccess  
  Notes ; This work was supported by EUROTAPES, a collaborative project funded by the European Commission's Seventh Framework Program (FP7/2007-2013) under Grant Agreement no. 280432. ; Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:141961 Serial 4693  
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Author Pahlke, P.; Lao, M.; Eisterer, M.; Meledin, A.; Van Tendeloo, G.; Hanisch, J.; Sieger, M.; Usoskin, A.; Stromer, J.; Holzapfel, B.; Schultz, L.; Huhne, R. pdf  url
doi  openurl
  Title Reduced Anisotropy and Enhanced In-Field Performance of Thick BaHfO3-Doped Films on ABAD-YSZ Templates Type A1 Journal article
  Year (down) 2016 Publication IEEE transactions on applied superconductivity Abbreviated Journal  
  Volume 26 Issue 26 Pages 1-4  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Pure and 6 mol% BaHfO3 (BHO) doped YBa2Cu3O7-δ (YBCO) films were prepared on CeO2-buffered ABAD-YSZ templates by pulsed laser deposition. The self-field Jc at 77 K reaches 1.1 MA/cm² in the doped sample compared to 2.5 MA/cm² in pure YBCO, at a film thickness of around 1 μm. Above a magnetic field of 2.2 T along B||c, Jc of the BHO-doped sample exceeds the Jc of the undoped film. The maximum pinning force density (FP,max) reaches a value of around 3 GN/cm² for both samples, but B(FP,max) increases from 1.4 T (pure) to a value of 2.9 T (BHO:YBCO). The Jc anisotropy curves of the doped sample show a large and broad peak at B||c and a strongly reduced anisotropy at all temperatures and fields compared to the pure sample. A complex defect structure with YBa2Cu4O8 intergrowths, Y2O3 precipitates and BHO nanocolumns with a fanshaped structure is observed by TEM investigations, which can explain the measured Jc(B,θ) behavior.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000376189700001 Publication Date 2016-03-14  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1051-8223 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 14 Open Access  
  Notes This work was supported by EUROTAPES, a collaborative project funded by the European Union’s Seventh Framework Program (FP7 / 2007 – 2013) under Grant Agreement n.280432. Approved Most recent IF: NA  
  Call Number c:irua:133779 Serial 4078  
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Author Sieger, M.; Pahlke, P.; Hanisch, J.; Sparing, M.; Bianchetti, M.; MacManus-Driscoll, J.; Lao, M.; Eisterer, M.; Meledin, A.; Van Tendeloo, G.; Nast, R.; Schultz, L.; Holzapfel, B.; Huhne, R. pdf  url
doi  openurl
  Title Ba2Y(Nb/Ta)O6–Doped YBCO Films on Biaxially Textured Ni–5at.% W Substrates Type A1 Journal article
  Year (down) 2016 Publication IEEE transactions on applied superconductivity Abbreviated Journal  
  Volume 26 Issue 26 Pages 1-5  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The incorporation of nanoscaled pinning centers in superconducting YBa2Cu3O7-d (YBCO) films is one of the core topics to enhance the critical current density Jc(B, Q) of coated conductors. The mixed double-perovskite Ba2Y(Nb/Ta)O6 (BYNTO) can be grown in nanosized columns parallel the YBCO c-axis and in step-like patterns, making it customizable to meet specific working conditions (T, B, Q). We compare a 1.6 μm thick film of pure YBCO and a similar film with additional 5 mol% of BYNTO, grown by pulsed laser deposition with a growth rate of 1.6 nm/s on buffered biaxially textured Ni-5at.% W tape. Our doped sample shows nanosized BYNTO columns parallel cYBCO and plates in the ab-plane containing Y, Nb and Ta. An improved homogeneity of the critical current density Jc over the sample was evaluated from trapped field profiles measured with a scanning Hall probe microscope. The mean Jc in rolling direction of the tape is 1.8 MA/cm² (77 K, self-field) and doubles the value of the undoped sample. Angular dependent measurements of the critical current density, Jc(Q), show a decreased anisotropy of the doped film for various magnetic fields at 77 K as well as 64 K.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000375581500001 Publication Date 2016-03-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1051-8223 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited 6 Open Access  
  Notes This work was supported by EUROTAPES, a collaborative project funded by the European Commission’s Seventh Framework Program (FP7 / 2007 – 2013) under Grant Agreement n.280432. Approved Most recent IF: NA  
  Call Number c:irua:133781 Serial 4079  
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Author Opherden, L.; Sieger, M.; Pahlke, P.; Hühne, R.; Schultz, L.; Meledin, A.; Van Tendeloo, G.; Nast, R.; Holzapfel, B.; Bianchetti, M.; MacManus-Driscoll, J.L.; Hänisch, J. url  doi
openurl 
  Title Large pinning forces and matching effects in YBa2Cu3O7-δ thin films with Ba2Y(Nb/Ta)O6 nano-precipitates Type A1 Journal article
  Year (down) 2016 Publication Scientific reports Abbreviated Journal Sci Rep-Uk  
  Volume 6 Issue 6 Pages 21188  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The addition of mixed double perovskite Ba2Y(Nb/Ta)O6 (BYNTO) to YBa2Cu3O7−δ (YBCO) thin films leads to a large improvement of the in-field current carrying capability. For low deposition rates, BYNTO grows as well-oriented, densely distributed nanocolumns. We achieved a pinning force density of 25 GN/m3 at 77 K at a matching field of 2.3 T, which is among the highest values reported for YBCO. The anisotropy of the critical current density shows a complex behavior whereby additional maxima are developed at field dependent angles. This is caused by a matching effect of the magnetic fields c-axis component. The exponent N of the current-voltage characteristics (inversely proportional to the creep rate S) allows the depinning mechanism to be determined. It changes from a double-kink excitation below the matching field to pinning-potential-determined creep above it.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000370364500001 Publication Date 2016-02-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2045-2322 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.259 Times cited 39 Open Access  
  Notes The authors gratefully acknowledge J. Scheiter, U. Besold, and U. Fiedler for technical assistance. This work was financially supported by EUROTAPES, a collaborative project funded by the European Commission’s Seventh Framework Program (FP7 / 2007-2013) under Grant Agreement no. 280432. Approved Most recent IF: 4.259  
  Call Number c:irua:131920 Serial 4026  
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Author Molina-Luna, L.; Duerrschnabel, M.; Turner, S.; Erbe, M.; Martinez, G.T.; Van Aert, S.; Holzapfel, B.; Van Tendeloo, G. pdf  doi
openurl 
  Title Atomic and electronic structures of BaHfO3-doped TFA-MOD-derived YBa2Cu3O7−δthin films Type A1 Journal article
  Year (down) 2015 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech  
  Volume 28 Issue 28 Pages 115009  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Tailoring the properties of oxide-based nanocomposites is of great importance for a wide range of materials relevant for energy technology. YBa2Cu3O7−δ (YBCO) superconducting thin films containing nanosized BaHfO3 (BHO) particles yield a significant improvement of the magnetic flux pinning properties and a reduced anisotropy of the critical current density. These films were prepared by chemical solution deposition (CSD) on (100) SrTiO3 (STO) substrates yielding critical current densities up to 3.6 MA cm−2 at 77 K and self-field. Transport in-field J c measurements demonstrated a high pinning force maximum of around 6 GN/m3 for a sample annealed at T = 760 °C that has a doping of 12 mol% of BHO. This sample was investigated by scanning transmission electron microscopy (STEM) in combination with electron energy-loss spectroscopy (EELS) yielding strain and spectral maps. Spherical BHO nanoparticles of 15 nm in size were found in the matrix, whereas the particles at the interface were flat. A 2 nm diffusion layer containing Ti was found at the YBCO (BHO)/STO interface. Local lattice deformation mapping at the atomic scale revealed crystal defects induced by the presence of both sorts of BHO nanoparticles, which can act as pinning centers for magnetic flux lines. Two types of local lattice defects were identified and imaged: (i) misfit edge dislocations and (ii) Ba-Cu-Cu-Ba stacking faults (Y-248 intergrowths). The local electronic structure and charge transfer were probed by high energy resolution monochromated electron energy-loss spectroscopy. This technique made it possible to distinguish superconducting from non-superconducting areas in nanocomposite samples with atomic resolution in real space, allowing the identification of local pinning sites on the order of the coherence length of YBCO (~1.5 nm) and the determination of 0.25 nm dislocation cores.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000366193000018 Publication Date 2015-09-25  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0953-2048;1361-6668; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.878 Times cited 4 Open Access  
  Notes The authors thank financial support from the European Union under the Framework 6 program as a contract for an Integrated Infrastructure Initiative (References No. 026019 ESTEEM) and by the EUFP6 Research Project “NanoEngineered Superconductors for Power Applications” NESPA no. MRTN-CT-2006-035619. This work was supported by funding from the European Research Council under the Seventh Framework Programme (FP7). L.M.L, S.T. and G.V.T acknowledge ERC grant N°246791 – COUNTATOMS and funding under a contract for an Integrated Infrastructure Initiative, Reference No. 312483- ESTEEM2, as well as the EC project EUROTAPES. G.T.M. and S.V.A acknowledge financial support from the Fund for Scientific Research-Flanders (Reference G.0064.10N and G.0393.11N). M.D. acknowledges financial support from the LOEWE research cluster RESPONSE (Hessen, Germany). M.E. has received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement n° NMP-LA-2012-280432.; esteem2jra2; esteem2jra3 Approved Most recent IF: 2.878; 2015 IF: 2.325  
  Call Number c:irua:129199 c:irua:129199 Serial 3942  
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Author Erbe, M.; Hänisch, J.; Hühne, R.; Freudenberg, T.; Kirchner, A.; Molina-Luna, L.; Damm, C.; Van Tendeloo, G.; Kaskel, S.; Schultz, L.; Holzapfel, B. pdf  doi
openurl 
  Title BaHfO3artificial pinning centres in TFA-MOD-derived YBCO and GdBCO thin films Type A1 Journal article
  Year (down) 2015 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech  
  Volume 28 Issue 28 Pages 114002  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Chemical solution deposition (CSD) is a promising way to realize REBa2Cu3O7−x (REBCO;RE = rare earth (here Y, Gd))-coated conductors with high performance in applied magnetic fields. However, the preparation process contains numerous parameters which need to be tuned to achieve high-quality films. Therefore, we investigated the growth of REBCO thin films containing nanometre-scale BaHfO3 (BHO) particles as pinning centres for magnetic flux lines, with emphasis on the influence of crystallization temperature and substrate on the microstructure and superconductivity. Conductivity, microscopy and x-ray investigations show an enhanced performance of BHO nano-composites in comparison to pristine REBCO. Further, those measurements reveal the superiority of GdBCO to YBCO—e.g. by inductive critical current densities, Jc, at self-field and 77 K. YBCO is outperformed by more than 1 MA cm−2 with Jc values of up to 5.0 MA cm−2 for 265 nm thick layers of GdBCO(BHO) on lanthanum aluminate. Transport in-field Jc measurements demonstrate high pinning force maxima of around 4 GN m−3 for YBCO(BHO) and GdBCO(BHO). However, the irreversibility fields are appreciably higher for GdBCO. The critical temperature was not significantly reduced upon BHO addition to both YBCO and GdBCO, indicating a low tendency for Hf diffusion into the REBCO matrix. Angular-dependent Jc measurements show a reduction of the anisotropy in the same order of magnitude for both REBCO compounds. Theoretical models suggest that more than one sort of pinning centre is active in all CSD films.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000366193000003 Publication Date 2015-09-25  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0953-2048;1361-6668; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.878 Times cited 36 Open Access  
  Notes Experimental work was mainly done at IFW Dresden. We thank Juliane Scheiter and Dr Jens Ingolf Mönch of IFW Dresden for technical assistance. The research leading to these results received funding from EUROTAPES, a collaborative project funded by the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement no. NMP-LA-2012-280 432. L Molina-Luna and G Van Tendeloo acknowledge funding from the European Research Council (ERC grant nr. 24 691-COUNTATOMS). Approved Most recent IF: 2.878; 2015 IF: 2.325  
  Call Number c:irua:129200 Serial 3941  
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Author Molina, L.; Egoavil, R.; Turner, S.; Thersleff, T.; Verbeeck, J.; Holzapfel, B.; Eibl, O.; Van Tendeloo, G. pdf  doi
openurl 
  Title Interlayer structure in YBCO-coated conductors prepared by chemical solution deposition Type A1 Journal article
  Year (down) 2013 Publication Superconductor science and technology Abbreviated Journal Supercond Sci Tech  
  Volume 26 Issue 7 Pages 075016-75018  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract The functionality of YBa2Cu3O7−δ (YBCO)-coated conductor technology depends on the reliability and microstructural properties of a given tape or wire architecture. Particularly, the interface to the metal tape is of interest since it determines the adhesion, mechanical stability of the film and thermal contact of the film to the substrate. A trifluoroacetate (TFA)metal organic deposition (MOD) prepared YBCO film deposited on a chemical solution-derived buffer layer architecture based on CeO2/La2Zr2O7 and grown on a flexible Ni5 at.%W substrate with a {100}⟨001⟩ biaxial texture was investigated. The YBCO film had a thickness was 440 nm and a jc of 1.02 MA cm−2 was determined at 77 K and zero external field. We present a sub-nanoscale analysis of a fully processed solution-derived YBCO-coated conductor by aberration-corrected scanning transmission electron microscopy (STEM) combined with electron energy-loss spectroscopy (EELS). For the first time, structural and chemical analysis of the valence has been carried out on the sub-nm scale. Intermixing of Ni, La, Ce, O and Ba takes place at these interfaces and gives rise to nanometer-sized interlayers which are a by-product of the sequential annealing process. Two distinct interfacial regions were analyzed in detail: (i) the YBCO/CeO2/La2Zr2O7 region (10 nm interlayer) and (ii) the La2Zr2O7/Ni5 at.%W substrate interface region (20 nm NiO). This is of particular significance for the functionality of these YBCO-coated conductor architectures grown by chemical solution deposition.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Bristol Editor  
  Language Wos 000319973800024 Publication Date 2013-05-28  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0953-2048;1361-6668; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.878 Times cited 11 Open Access  
  Notes vortex; Countatoms; Fwo; Esteem2; esteem2jra2; esteem2jra3 ECASJO_; Approved Most recent IF: 2.878; 2013 IF: 2.796  
  Call Number UA @ lucian @ c:irua:108704UA @ admin @ c:irua:108704 Serial 1698  
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