paper

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

arXiv:1501.05931 · doi:10.1088/0953-2048/28/5/055017

Abstract

We measure magnetization as a function of temperature, magnetic field and time in a BaFe $_{2}$ (As $_{0.68}$ P $_{0.32}$ ) $_{2}$ single crystal with $T_{c}$ = 27.6 K. The fish-tail observed on many $M$ ( $H$ ) curves are used to construct isofield $M$ ( $T$ ) curves which show an anomalous peak at some temperature $T t$ suggesting a possible phase transition in the irreversible regime. A vortex dynamics study performed along the peaks evidences a minimum in the relaxation rate occurring at the same position $T t$ of the minimum value of $M$ in these peaks. A vortex dynamics study performed on $M$ ( $H$ ) curves show two distinct minimum in the relaxation rate: a first minimum ( $H 1$ ) for a lower field correlating with $T t$ and a second ( $H 2$ ) correlating with the peak in the fish-tail. A phase diagram is constructed and the line corresponding to $T t$ and $H 1$ points obey an expression developed in the literature for a structural rhombic to square lattice phase transition, further supporting this view.

11 pages, single column, 5 figures, submitted to Superc. Scien. and Technology

Experimental observation of an anomalous peak in isofield M(T) curves in BaFe2​(As1−x​Px​)2​ resembling the fish-tail in M(H) curves further suggesting a possible phase transition in the irreversible regime

Abstract

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