Superconducting Films

The preparation and investigation of superconducting thin films is of high importance for both basic research and future applications of superconductivity. Especially epitaxially grown single crystalline thin films and heterostructures  offer the possibility to study in detail fundamental properties of superconductors.

The current research of the superconducting materials group in this field is focused on the investigation and control of pinning properties of High Temperature Superconductors (HTSC) to improve their current carrying capabilities,  as well as on the interaction of superconductivity and magnetism in  artificial heterostructures of superconducting and magnetic thin films. The recently discovered pnictide based superconductors are currently a highly interesting research topic in the group and thin films of LaOFFeAs and Co-doped BaFe₂As₂ were already successfully prepared..

Epitaxially grown REBa₂Cu₃O_x films on flexible, highly textured metal tapes are currently under intense investigation since these so called “Coated Conductors” can be used as HTSC wires for power applications, offering enormous application potential in the power electric sector. We use both Pulsed Laser Deposition (PLD) and Chemical Solution Deposition (CSD) methods for evaluating these opportunities of HTSC thin films.   

To characterize the stoichiometry and microstructure of the prepared films a variety of high level techniques like ICP analysis, X-ray pole figure analysis, Electron Backscatter Diffraction (EBSD) or TEM are used. The superconducting properties are mainly investigated by electrical transport and magnetization measurements.

Recent Publications

M. Kidszun, S. Haindl, E. Reich, J. Hänisch, K. Iida, L. Schultz, B. Holzapfel,
"Epitaxial LaFeAsO_1–xF_x thin films grown by pulsed laser deposition",
Supercond. Sci. Technol. 23 (2010) 022002

S. Haindl, M. Kidszun, A. Kauffmann, K. Nenkov, N. Kozlova, J. Freudenberger, T. Thersleff, J. Hänisch, J. Werner, E. Reich, L. Schultz, B. Holzapfel: "LaFeAsO_1-xF_x thin films: high upper critical fields and evidence of weak link behavior",
Phys. Rev. Lett. 104 (2010) 077001

K. Iida, J. Hänisch, R. Hühne, F. Kurth, M. Kidszun, S. Haindl, J. Werner, L. Schultz, B. Holzapfel,
"Strong T_C dependence for strained epitaxial Ba(Fe_1-xCo_x)₂As₂ thin films",
Appl. Phys. Lett. 95 (2009) 192501

Hänisch, J., Cai, C., Stehr, V., Hühne, R., Lyubina, J., Nenkov, K., Fuchs, G., Schultz, L., Holzapfel, B.:
"Formation and pinning properties of growth-controlled nanoscale precipitates in YBa₂Cu₃O_7-d/transition metal quasi-multilayers", Supercond. Sci. Technol. 19 (2006) 534-540

Hänisch, J., Cai, C., Hühne, R., Schultz, L., Holzapfel, B.:
„Formation of nanosized BaIrO₃ precipitates and their contribution to flux pinning in Ir-doped YBa₂Cu₃O_7-δ quasi-multilayers“, Appl. Phys. Lett. 86 (2005) 122508

Cai, C., Hänisch, J., Hühne, R., Stehr, V., Mickel, C., Gemming, T., Holzapfel, B.:
„Structural and magnetotransport properties of YBa₂Cu₃O_7-δ/Y₂O₃ quasimultilayers”,
J. Appl. Physics 98 (2005) 123906