A5055399621- Physics of Superconductivity and Magnetism
- Iron-based superconductors research
- Magnetic and transport properties of perovskites and related materials
- Superconductivity in MgB2 and Alloys
- Advanced Condensed Matter Physics
- Corporate Taxation and Avoidance
- Magnetic properties of thin films
- Rare-earth and actinide compounds
- ZnO doping and properties
- Electronic and Structural Properties of Oxides
- Superconducting Materials and Applications
- Intellectual Capital and Performance Analysis
- Semiconductor materials and devices
- Acoustic Wave Resonator Technologies
- Copper Interconnects and Reliability
- Magnetic Properties of Alloys
- Ferroelectric and Piezoelectric Materials
- Mesoporous Materials and Catalysis
- Metal and Thin Film Mechanics
- Superconducting and THz Device Technology
- Magnetic Properties and Applications
- Theoretical and Computational Physics
- Plasma Diagnostics and Applications
- Quantum and electron transport phenomena
- Electrophoretic Deposition in Materials Science
Karlsruhe Institute of Technology
2016-2025
Stockholm University
2020
Ghent University
2020
Leibniz Institute for Solid State and Materials Research
2009-2018
Institute on Taxation and Economic Policy
2018
Nagoya University
2014
Central Research Institute of Electric Power Industry
2014
iBeam Materials (United States)
2014
Leibniz Association
2005-2013
Leibniz Institute for Neurobiology
2002-2012
High temperature superconducting (HTS) tape can be cut and stacked to generate large magnetic fields at cryogenic temperatures after inducing persistent currents in the layers. A field of 17.7 T was trapped between two stacks HTS 8 K with no external mechanical reinforcement. 17.6 could sustained when warming stack up 14 K. new type hybrid used consisting a 12 mm square insert embedded inside larger 34.4 diameter made from different tape. The generated is largest for any magnet reported 30%...
Structural and transport measurements for quasimultilayers of Ir-doped YBa2Cu3O7−δ prepared by pulsed-laser deposition are presented. Due to metallic Ir doping, BaIrO3 particles form during film growth. These nanosized particles, having a perovskite structure, grow epitaxially in cube-on-cube relationship inside the film. A strong increase pinning force density and, hence, Jc was found.
Ba ( Fe 1 − x Co ) 2 As superconducting thin films have been grown on SrTiO3, (La,Sr)(Al,Ta)O3, LaAlO3, and YAlO3 (YAO) single crystal substrates by pulsed laser deposition. All the films, except YAO, epitaxially without buffer layers. The deposited YAO contained 45° in-plane rotated grains showed a broad transition. onset Tc of is observed to increase from 16.2 24.5 K with increasing c/a, mainly due slight distortion AsFe4 tetrahedron. From this correlation, we expect that higher transition...
Abstract The addition of mixed double perovskite Ba 2 Y(Nb/Ta)O 6 (BYNTO) to YBa Cu 3 O 7−δ (YBCO) thin films leads a large improvement the in-field current carrying capability. For low deposition rates, BYNTO grows as well-oriented, densely distributed nanocolumns. We achieved pinning force density 25 GN/m at 77 K matching field 2.3 T, which is among highest values reported for YBCO. anisotropy critical shows complex behavior whereby additional maxima are developed dependent angles. This...
Abstract The European Union-funded Advanced Superconducting Motor Experimental Demonstrator (ASuMED) project started in May 2017 with the purpose of demonstrating benefits a new, fully superconducting motor for reaching targets established by Flightpath 2050 plan. aims at power density 20kW kg −1 using high-temperature (HTS) stator. rotor will use HTS stacks operating like permanent magnets. A highly efficient cryostat combined an integrated cryogenic cooling system and associated converter...
The biaxially textured growth of superconducting Co-doped BaFe2As2 (Ba-122) thin films has been realized on ion beam assisted deposition (IBAD) MgO coated conductor templates by employing an iron buffer architecture. pnictide showed a transition temperature 21.5 K, which is slightly lower than that Ba-122 single crystalline substrates. A self-field critical current density over 105 A·cm-2 already achieved even at 8 K. experiment highlights the potential possible applications iron-based...
The angular-dependent critical current density, Jc(theta), and the upper field, Hc2(theta), of epitaxial Ba(Fe1-xCox)2As2 thin films have been investigated. No Jc(theta) peaks for H || c were observed regardless temperatures magnetic fields. In contrast, showed a broad maximum at theta=90 degree, which arises from intrinsic pinning. All data except degree can be scaled by Blatter plot. Hc2(theta) near Tc follows anisotropic Ginzburg-Landau expression. mass anisotropy increased 1.5 to 2 with...
Superconducting LaFeAsO1-xFx thin films were grown on single crystalline LaAlO3 substrates with critical temperatures (onset) up to 28 K. Resistive measurements in high magnetic fields 40 T reveal a paramagnetically limited upper field mu{0}H{c2}(0) around 77 and remarkable steep slope of -6.2 K-1 near T{c}. From transport we observed weak-link behavior low evidence for broad reversible regime.
Having succeeded in the fabrication of epitaxial superconducting LaFeAsO(1-x)F(x) thin films we performed an extensive study electrical transport properties. In face multiband superconductivity can demonstrate that anisotropic Ginzburg-Landau scaling angular dependent critical current densities be adopted, although being originally developed for single band superconductors. contrast with superconductors mass anisotropy is temperature dependent. A very steep increase upper field and...
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 be tuned achieve high-quality films. Therefore, we investigated growth of REBCO thin films containing nanometre-scale BaHfO3 (BHO) particles as pinning centres for flux lines, emphasis on influence crystallization temperature and substrate...
We report on the transport properties of clean, epitaxial Fe(Se,Te) thin films prepared Fe-buffered MgO (001) single crystalline substrates by pulsed laser deposition. Near ${T}_{\mathrm{c}}$ a steep slope upper critical field for $H||ab$ was observed (74.1 T/K), leading to very short out-of-plane coherence length, ${\ensuremath{\xi}}_{\mathrm{c}}(0)$, 0.2 nm, yielding 2${\ensuremath{\xi}}_{\mathrm{c}}(0)\ensuremath{\approx}0.4\phantom{\rule{0.16em}{0ex}}\mathrm{nm}$. This value is shorter...
Abstract In general, the critical current density, J c , of type II superconductors and its anisotropy with respect to magnetic field orientation is determined by intrinsic extrinsic properties. The Fe-based ‘122’ family their moderate electronic anisotropies high yet accessible fields ( H c2 irr ) are a good model system study this interplay. paper, we explore vortex matter optimally Co-doped BaFe 2 As thin films extended planar -axis correlated defects. temperature angular dependence upper...
Thin films of Fe-based superconductors (FBS) have been utilized in a plethora different experiments for fundamental understanding the superconductivity these materials, as well and improving materials with regard to possible applications.The developments progress thin film growth past 10 years are reviewed focus on two main deposition techniques used so far FBS (pulsed laser deposition, molecular beam epitaxy).Possible choices substrates or buffer systems motivated explained misfit, thermal...
Achieving low cost, safe, reproducible, and high performance superconducting thin films of YBa2Cu3O7−δ is essential to bring this material the energy market. Here, we report on chemical solution deposition nanocomposites from environmentally benign precursors with a fluorine content. Preformed ZrO2 nanocrystals (3.5 nm) were stabilized in methanolic precursor via two strategies: charge stabilization steric stabilization. Counterintuitively, did not result quality layers, while resulted...
Understanding the nature of grain boundary (GB) characteristics in combination with creating low-energy GBs by modifying processing conditions, so-called GB engineering, is great importance for controlling and reducing defect density, leading to improved functionalities polycrystalline metals ceramics. For superconductors particularly, including both low- high-temperature superconductors, engineering has been developed improve especially critical current densities, Jc, across these GBs. The...
${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7}/{\mathrm{Y}\mathrm{S}\mathrm{Z}/\mathrm{C}\mathrm{e}\mathrm{O}}_{2}$ heterostructures have been grown epitaxially on biaxially textured Ni substrates by pulsed laser deposition. The texture of the film was determined electron backscattering diffraction, providing information propagation grain boundary network from substrate to ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7}$ via epitaxial growth. limits critical current density 0.3...
High-quality mono rare earth $R{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ (R=Gd,Eu,Nd) and mixed $({\mathrm{Gd}}_{1/3}{\mathrm{Eu}}_{1/3}{\mathrm{Nd}}_{1/3}){\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ (GEN123) films were prepared by off-axis laser deposition, their transport flux pinning characteristics experimentally studied. Enhanced due to mixing is evidenced high critical current density ${(J}_{c})$ an...
We demonstrate the growth of epitaxial Fe/Ba(Fe(1-x)Co(x))2As2 (Fe/Ba-122) bilayers on MgO(001) and LSAT(001) single crystal substrates using Pulsed Laser Deposition (PLD). By exploiting metallic nature FeAs tetrahedron in Ba-122 structure, we achieve a coherent interfacial bond between bcc iron Co-doped Ba-122. Tc values for both were close to that PLD target. Direct observation bonding Fe sublattice by atomic resolution transmission electron microscopy implies this bilayer architecture may...
For developing commercially utilized high-performance high-temperature superconductors, the fabrication of biaxially textured (RE)Ba2Cu3O7−x (REBCO, RE = Y, Gd) coated conductors via metal–organic decomposition trifluoroacetate precursors (TFA-MOD) has become an interesting strategy for industrial scale-up due to low costs and simple operation. However, hygroscopic nature commonly used precursor solutions makes them very sensitive water pollution through air humidity. This can lead a...
Optimized, biaxially textured BaFe1.8Co0.2As2 thin films with an in-plane alignment of 1.7° have been realized on high-quality IBAD-textured MgO-coated technical substrates utilizing additional Fe buffer layers. High critical current densities (Jc) were achieved, comparable to single crystalline MgO (Jc ≥ 1 MA cm−2 at 4 K, self-field). Transmission electron microscopy investigations reveal a small number c-axis correlated defects introduced by the template. The effect these Jc anisotropy was...
The recently discovered oxypnictide superconductor SmFeAs(O,F) is the most attractive material among Fe-based superconductors due to its highest transition temperature of 56 K and potential for high-field performance. In order exploit this new superconducting applications, knowledge understanding electro-magnetic properties are needed. Recent success in fabricating epitaxial thin films opens a great opportunity explore their transport properties. Here we report on high critical current...
The discovery of Fe-based superconductors (FBS) as the second class high-temperature superconducting transition (high-Tc) materials after cuprates generated a significant impact on community fundamental and applied superconductivity research. Whenever new high-Tc is discovered, lot effort devoted to growing single crystals epitaxial thin films for exploring basic physical quantities. Although several properties FBS are similar (large upper critical fields, resulting from short coherence...
Chemical solution deposition (CSD) of YBa2Cu3O7−δ (YBCO) nanocomposites from colloidal precursor solutions containing double metal oxide preformed nanocrystals is a promising, cost-effective, and reproducible approach to producing superconducting films with high critical current density (Jc) enhanced pinning. Here, the influence nanocrystal composition on microstructure properties YBCO nanocomposite studied, focus establishing simple scalable process grow that can be transferred nanoadded...
Symmetry elegantly governs the fundamental properties and derived functionalities of condensed matter. For instance, realizing superconducting diode effect (SDE) demands breaking space-inversion time-reversal symmetries simultaneously. Although SDE is widely observed in various platforms, its underlying mechanism remains debated, particularly regarding role vortices. Here, we systematically investigate nonreciprocal transport chiral type-I superconductor NbGe2. Moreover, induce type-II...