Unusually high critical current of clean P-doped BaFe{sub 2}As{sub 2} single crystalline thin film

Journal Article · Mon Feb 16 00:00:00 EST 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4908257· OSTI ID:22412661

Engelmann, J.; Schultz, L. ^[1]; TU Dresden, 01062 Dresden ^[2]; Tarantini, C.; Jaroszynski, J. ^[3]; Grinenko, V.; Reich, E.; Hühne, R. ^[1]; Hänisch, J. ^[1]; Mori, Y.; Sakagami, A.; Kawaguchi, T.; Ikuta, H. ^[4]; Holzapfel, B. ^[5]

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1. Institute for Metallic Materials, IFW Dresden, 01171 Dresden (Germany)
2. Germany
3. Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University, 2031 East Paul Dirac Drive, Tallahassee, Florida 32310 (United States)
4. Department of Crystalline Materials Science, Nagoya University, Chikusa, Nagoya 464-8603 (Japan)
5. Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann von Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

Microstructurally clean, isovalently P-doped BaFe{sub 2}As{sub 2} (Ba-122) single crystalline thin films have been prepared on MgO (001) substrates by molecular beam epitaxy. These films show a superconducting transition temperature (T{sub c}) of over 30 K although P content is around 0.22, which is lower than the optimal one for single crystals (i.e., 0.33). The enhanced T{sub c} at this doping level is attributed to the in-plane tensile strain. The strained film shows high transport self-field critical current densities (J{sub c}) of over 6 MA/cm{sup 2} at 4.2 K, which are among the highest for Fe based superconductors (FeSCs). In-field J{sub c} exceeds 0.1 MA/cm{sup 2} at μ{sub 0}H=35 T for H‖ab and μ{sub 0}H=18 T for H‖c at 4.2 K, respectively, in spite of moderate upper critical fields compared to other FeSCs with similar T{sub c}. Structural investigations reveal no defects or misoriented grains pointing to strong pinning centers. We relate this unexpected high J{sub c} to a strong enhancement of the vortex core energy at optimal T{sub c}, driven by in-plane strain and doping. These unusually high J{sub c} make P-doped Ba-122 very favorable for high-field magnet applications.

• OSTI ID: 22412661
• Journal Information: Applied Physics Letters, Vol. 106, Issue 7; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BARIUM COMPOUNDS
COMPARATIVE EVALUATIONS
CRITICAL CURRENT
CRITICAL FIELD
CURRENT DENSITY
DOPED MATERIALS
IRON ARSENIDES
MAGNESIUM OXIDES
MAGNETS
MICROSTRUCTURE
MOLECULAR BEAM EPITAXY
MONOCRYSTALS
STRAINS
SUBSTRATES
SUPERCONDUCTORS
THIN FILMS
TRANSITION TEMPERATURE
VORTICES