Strong pinning in the hole-doped pnictide superconductor La${}_{0.34}$Na${}_{0.66}$Fe${}_2$As${}_2$

Abstract

We present magnetization studies as a function of time, temperature and magnetic field for $H$ $\parallel$ c-axis, in a hole-doped pnictide superconductor, La${}_{0.34}$Na${}_{0.66}$Fe${}_2$As${}_2$, with, $T_c$ $\approx$ 27 K. The obtained vortex phase-diagram shows that the magnetic irreversibility line is very close to the mean-field superconducting transition line, similar to the low $T_c$ superconductors, evidencing a strong pinning behavior. The irreversibility line does not follow a power law behavior with ($T_c$-$T$), however, it is well described using an expression developed in the literature considering the effect of disorder in the system. The critical current density estimated using the Bean's critical-state model is found to be of the order of 10${}^5$ A/cm${}^2$ below 12 K in the limit of zero magnetic field. A plot of the normalized pinning force density as a function of the reduced magnetic field at different temperatures shows a good scaling and the analysis suggests that the vortex pinning is due to normal point like pinning centers. The temperature dependence of the critical current density suggests that the pinning due to the variation in charge carrier mean free path alone is not sufficient to explain the experimental data. Magnetic relaxation rate as a function of temperature and magnetic field is also studied.

19 pages, 6 Figures, Accepted for Publication in the "Journal of Applied Physics 2019"

References in corpus (13)

• Nearly Isotropic superconductivity in (Ba,K)Fe2As2
• Small anisotropy, weak thermal fluctuations, and high field superconductivity in Co-doped iron pnictide Ba(Fe1-xCox)2As2
• High intergrain critical current density in fine-grain (Ba0.6K0.4)Fe2As2 wires and bulks
• Fishtail effect and the vortex phase diagram of single crystal Ba0.6K0.4Fe2As2
• Upper critical fields well above 100 T for the superconductor SmFeAsO${}_{0.85}$F${}_{0.15}$ with T${}_c$ = 46 K
• Doping-dependent critical current properties in K, Co, and P-doped BaFe2As2 single crystals
• Lower critical field and SNS-Andreev spectroscopy of 122-arsenides: Evidence of nodeless superconducting gap
• Plastic pinning replaces collective pinning as the second magnetization peak disappears in the pnictide superconductor Ba-KFe${}_2$As${}_2$
• Nodeless superconductivity in the presence of spin-density wave in pnictide superconductors: The case of BaFe${}_{2-x}$Ni${}_x$As${}_2$
• Magnetic and structural transitions in La${}_{0.4}$Na${}_{0.6}$Fe${}_2$As${}_2$ single crystals
• Experimental observation of an anomalous peak in isofield M(T) curves in BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ resembling the fish-tail in $M$($H$) curves further suggesting a possible phase transition in the irreversible regime
• Study of the second magnetization peak and the pinning behaviour in Ba(Fe${}_{0.935}$Co${}_{0.065}$)${}_2$As$_2
• Vortex dynamics as a function of field orientation in BaFe1.9Ni0.1As2

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• Second magnetization peak, anomalous field penetration, and Josephson vortices in KCa${}_2$Fe${}_4$As${}_4$F${}_2$ bilayer pnictide superconductor