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Structural and chemical properties of superconducting Co-doped BaFe$_2$As$_2$ thin films grown on CaF$_2$

Grünewald, Lukas ORCID iD icon; Langer, Marco; Meyer, Sven; Nerz, Daniel; Hänisch, Jens ORCID iD icon; Holzapfel, Bernhard; Gerthsen, Dagmar

Abstract:
Thin films of Co-doped BaFe$_2$As$_2$ of similar thickness (~40 nm) were grown with different growth rates (0.4 Å s$^{-1}$ and 0.9 Å s$^{-1}$) by pulsed laser deposition on CaF$_2$(001) substrates. Analytical transmission electron microscopy (TEM) was applied to analyze the microstructure and secondary phases. The formation of BaF$_2$ and a high concentration of planar defects (mainly stacking faults) are observed for the sample grown at a low rate. A higher growth rate results in high-quality epitaxial films with only few antiphase boundaries. A higher $T_\text{c}$ was measured for the sample grown at a low growth rate, which is attributed to the difference in strain state induced by the high concentration of defects. Large crystalline Fe precipitates are observed in both samples. Chemical analysis shows a pronounced O and slight F content at the planar defects which highlights the role of O in defect formation. Electron-beam-induced irradiation damage during TEM measurements is observed and discussed.


Verlagsausgabe §
DOI: 10.5445/IR/1000127053
Veröffentlicht am 22.11.2021
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Technische Physik (ITEP)
Laboratorium für Elektronenmikroskopie (LEM)
Universität Karlsruhe (TH) – Zentrale Einrichtungen (Zentrale Einrichtungen)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 0953-2048, 1361-6668
KITopen-ID: 1000127053
HGF-Programm 37.06.02 (POF III, LK 01) New Power Network Technology
Weitere HGF-Programme 38.05.03 (POF IV, LK 01) High Temperature Superconductivity
Erschienen in Superconductor science and technology
Verlag Institute of Physics Publishing Ltd (IOP Publishing Ltd)
Band 34
Heft 3
Seiten Art.Nr. 035005
Vorab online veröffentlicht am 30.11.2020
Externe Relationen Supplement
Schlagwörter EELS, EDXS, STEM, Fe-based superconductor, Ba122, CaF2
Nachgewiesen in Dimensions
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