Effects of Co substitution on thermodynamic and transport properties and anisotropic H c 2 in Ba ( Fe 1 − x Co x ) 2 As 2 single crystals

By N. Ni, M. Tillman, Jiaqiang Yan, A. Kracher, S. Hannahs, S. Bud’ko, Paul C. Canfield. 2008

327 citations recorded by the source corpus.

Single crystalline samples of $\text{Ba}{({\text{Fe}}_{1\ensuremath{-}x}{\text{Co}}_{x})}_{2}{\text{As}}_{2}$ with $xl0.12$ have been grown and characterized via microscopic, thermodynamic, and transport measurements. With increasing Co substitution, the thermodynamic and transport signatures of the structural (high-temperature tetragonal to low-temperature orthorhombic) and magnetic (high-temperature nonmagnetic to low-temperature antiferromagnetic) transitions are suppressed at a rate of roughly 15 K/% Co. In addition, for $x\ensuremath{\ge}0.038$ superconductivity is stabilized, rising to a maximum ${T}_{c}$ of approximately 23 K for $x\ensuremath{\approx}0.07$ and decreasing for higher $x$ values. The $T\text{\ensuremath{-}}x$ phase diagram for $\text{Ba}{({\text{Fe}}_{1\ensuremath{-}x}{\text{Co}}_{x})}_{2}{\text{As}}_{2}$ indicates that either superconductivity can exist in both low-temperature crystallographic phases or that there is a structural phase separation. Anisotropic superconducting upper critical-field data $[{H}_{c2}(T)]$ show a significant and clear change in anisotropy between samples that have higher temperature structural phase transitions and those that do not. These data show that the superconductivity is sensitive to the suppression of the higher temperature phase transition.

Subfields: Accounting, Electronic, Optical and Magnetic Materials, Molecular Biology

View Paper: https://www.semanticscholar.org/paper/9dd14c09aae94a2e9f5916b1e071e7f141074739

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Citations in the corpus

Evidence for a Lifshitz transition in electron-doped iron arsenic superconductors at the onset of superconductivity (2010, background): “In the AE(Fe 1− x T x ) 2 As 2 family (known as ‘122’, with AE being Ca, Sr or Ba and T being a transition metal), the simultaneous structural/magnetic phase transition that occurs at elevated temperature in the undoped material splits and is suppressed by carrier dopin”
Superconductivity in iron compounds (2011, background): “…¼ 28 K) up to 60 T byYuan et al. (2009), on single crystal BaFe2 xCoxAs2 (x ¼ 0:076, 0.094, 0.116, 0.148, 0.20, 0.228; Tc ¼ 7, 15, 23, 22, 17, 8 K) up to 35 T by Ni et al. (2008b), and on single crystal BaFe2 xCoxAs2 (x ¼ 0:20;Tc ¼ 22 K) up to 35T by Putti et al. (2010) allow several conclusions.”
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).”