Determination of the phase diagram of the electron-doped superconductor Ba(Fe 1-x Co x ) 2 As 2

By J. Chu, J. Analytis, C. Kucharczyk, Ian R. Fisher. 2008

300 citations recorded by the source corpus.

Systematic measurements of the resistivity, heat capacity, susceptibility, and Hall coefficient are presented for single-crystal samples of the electron-doped superconductor $\text{Ba}{({\text{Fe}}_{1\ensuremath{-}x}{\text{Co}}_{x})}_{2}{\text{As}}_{2}$. These data delineate an $x\text{\ensuremath{-}}T$ phase diagram in which the single magnetic/structural phase transition that is observed for undoped ${\text{BaFe}}_{2}{\text{As}}_{2}$ at 134 K appears to split into two distinct phase transitions, both of which are rapidly suppressed with increasing Co concentration. Superconductivity emerges for Co concentrations above $x\ensuremath{\sim}0.025$ and appears to coexist with the broken-symmetry state for an appreciable range of doping up to $x\ensuremath{\sim}0.06$. The optimal superconducting transition temperature appears to coincide with the Co concentration at which the magnetic/structural phase transitions are totally suppressed, at least within the resolution provided by the finite-step size between crystals prepared with different doping levels. Superconductivity is observed for a further range of Co concentrations before being completely suppressed for $x\ensuremath{\sim}0.18$ and above. The form of this $x\text{\ensuremath{-}}T$ phase diagram is suggestive of an association between superconductivity and a quantum critical point arising from suppression of the magnetic and/or structural phase transitions.

Subfields: Condensed Matter Physics, Electronic, Optical and Magnetic Materials

View Paper: https://www.semanticscholar.org/paper/37093b1e6813a40e297bc5fcff64f5ed520e1cf4

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In Condensed Matter Physics

In Electronic, Optical and Magnetic Materials

Citations in the corpus

Fundamental studies of superconductors using scanning magnetic imaging (2010, background): “transition temperature to decrease [270, 271] falling to zero at”
In-plane electronic anisotropy of underdoped ‘122’ Fe-arsenide superconductors revealed by measurements of detwinned single crystals (2011, background): “The temperature difference monotonically increases with increasing concentration of the substituent, at least until the top of the superconducting dome (Ni et al 2008a, Chu et al 2009, Lester et al 2009, Nandi et al 2010, Ni et al 2010).”
Magnetism and its microscopic origin in iron-based high-temperature superconductors (2012, background): “From systematic transport and magnetic measurements of single crystals [73, 74], the phase diagram for BaFe2−xCoxAs2 was established, where the single structural/magnetic phase transition in BaFe2As2 splits with increasing Co-doping.”