# High J$_{c}$ and low anisotropy of hydrogen doped NdFeAsO superconducting thin film

Iida, Kazumasa; Hänisch, Jens ; Kondo, Keisuke; Chen, Mingyu; Hatano, Takafumi; Wang, Chao; Saito, Hikaru; Hata, Satoshi; Ikuta, Hiroshi

## Abstract:

The recent realisations of hydrogen doped LnFeAsO (Ln = Nd and Sm) superconducting epitaxial thin films call for further investigation of their structural and electrical transport properties. Here, we report on the microstructure of a NdFeAs(O,H) epitaxial thin film and its temperature, field, and orientation dependencies of the resistivity and the critical current density J$_{c}$. The superconducting transition temperature T$_{c}$ is comparable to NdFeAs(O,F). Transmission electron microscopy investigation supported that hydrogen is homogenously substituted for oxygen. A high self-field J$_{c}$ of over 10 MA/cm$^{2}$ was recorded at 5 K, which is likely to be caused by a short London penetration depth. The anisotropic Ginzburg–Landau scaling for the angle dependence of J$_{c}$ yielded temperature-dependent scaling parameters γ$_{J}$ that decreased from 1.6 at 30 K to 1.3 at 5 K. This is opposite to the behaviour of NdFeAs(O,F). Additionally, γ$_{J}$ of NdFeAs(O,H) is smaller than that of NdFeAs(O,F). Our results indicate that heavily electron doping by means of hydrogen substitution for oxygen in LnFeAsO is highly beneficial for achieving high J$_{c}$ with low anisotropy without compromising T$_{c}$, which is favourable for high-field magnet applications.

 Zugehörige Institution(en) am KIT Institut für Technische Physik (ITEP) Publikationstyp Zeitschriftenaufsatz Publikationsjahr 2021 Sprache Englisch Identifikator ISSN: 2045-2322 KITopen-ID: 1000130888 HGF-Programm 38.05.03 (POF IV, LK 01) High Temperature Superconductivity Erschienen in Scientific Reports Verlag Nature Research Band 11 Heft 1 Seiten Art.-Nr.: 5636 Nachgewiesen in DimensionsScopus
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