Distinct high-T transitions in underdoped Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$

R. R. Urbano; E. L. Green; W. G. Moulton; A. P. Reyes; P. L. Kuhns; E. M. Bittar; C. Adriano; T. M. Garitezi; L. Bufaiçal; P. G. Pagliuso

doi:10.1103/PhysRevLett.105.107001

paper

Distinct high-T transitions in underdoped Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$

arXiv:1005.3718 · doi:10.1103/PhysRevLett.105.107001

Abstract

In contrast to the simultaneous structural and magnetic first order phase transition $T_{0}$ previously reported, our detailed investigation on an underdoped Ba $_{0.84}$ K $_{0.16}$ Fe $_{2}$ As $_{2}$ single crystal unambiguously revealed that the transitions are not concomitant. The tetragonal ( $τ$ : I4/mmm) - orthorhombic ( $ϑ$ : Fmmm) structural transition occurs at $T_{S} ≃$ 110 K, followed by an adjacent antiferromagnetic (AFM) transition at $T_{N} ≃$ 102 K. Hysteresis and coexistence of the $τ$ and $ϑ$ phases over a finite temperature range observed in our NMR experiments confirm the first order character of the structural transition and provide evidence that both $T_{S}$ and $T_{N}$ are strongly correlated. Our data also show that superconductivity (SC) develops in the $ϑ$ phase below $T_{c}$ = 20 K and coexists with long range AFM. This new observation, $T_{S} \neq = T_{N}$ , firmly establishes another similarity between the hole-doped BaFe $_{2}$ As $_{2}$ via K substitution and the electron-doped iron-arsenide superconductors.

4 pages, 3 figures

Distinct high-T transitions in underdoped Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$

Abstract

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Distinct high-T transitions in underdoped Ba1−x​Kx​Fe2​As2​

Abstract

References in corpus (32)

Cited by in corpus (25)

Distinct high-T transitions in underdoped Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$