Fish-tail and vortex dynamics in Ni doped iron-pnictide BaFe{1.82}Ni_{0.18}As_2

Abstract

We study the vortex-dynamics of a BaFe{1.82}Ni_{0.18}As_2 crystal with Tc = 8 K, by measuring flux-creep over the second magnetisation (or fish-tail) peak for both H//c-axis and H//ab planes. Magnetic relaxation data show an anomalously long initial stage of relaxation, lasting approximately10 minutes for H//c-axis and 2-3 min for H//ab, resembling a transient effect with a lower relaxation rate, which is followed by the usual log(time) relaxation. Interestingly, study of the relaxation rate R vs H for both stages of relaxation and for both field directions, are featureless over the field range associated with the fish-tail. The same trend was confirmed by plotting R vs T obtained from flux-creep data measured as a function of temperature for a fixed field (H//$c-axis). A plot of the activation energy U(M,T) calculated from the time relaxation of the magnetisation at a fixed field also shows a smooth behavior further supporting the view that the fish-tail peak is not associated with a crossover in vortex pinning regime within the collective pinning scenario.

4 pages, 4 figures

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Cited by in corpus (12)

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• Critical current density and magnetic phase diagram of BaFe1.29Ru0.71As2 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
• Vortex Structure and Anisotropic Superconducting Gaps in Ba[Fe(Ni)]${}_2$As${}_2$
• Study of the second magnetization peak and the pinning behaviour in Ba(Fe${}_{0.935}$Co${}_{0.065}$)${}_2$As$_2
• Doping Dependence of the Second Magnetization Peak, Critical Current Density and Pinning Mechanism in BaFe${}_{2-x}$Ni${}_x$As${}_2$ Pnictide Superconductors
• Vortex dynamics and second magnetization peak in PrFeAsO${}_{0.60}$F${}_{0.12}$ superconductor
• Slow Vortex Creep Induced by Strong Grain Boundary Pinning in Advanced Ba122 Superconducting Tapes
• Vortex dynamics and second magnetization peak in the iron-pnictide superconductor Ca${}_{0.82}$La${}_{0.18}$Fe${}_{0.96}$Ni${}_{0.04}$As${}_2$
• Vortex dynamics as a function of field orientation in BaFe1.9Ni0.1As2