Superconductivity and magnetic and transport properties of single-crystalline CaK(Fe$_{1-x}$Cr$_{x}$)$_{4}$As$_{4}$

M. Xu; J. Schmidt; M. A. Tanatar; R. Prozorov; S. L. Bud'ko; P. C. Canfield

doi:10.1103/PhysRevB.107.134511

paper

Superconductivity and magnetic and transport properties of single-crystalline CaK(Fe $_{1 - x}$ Cr $_{x}$ ) $_{4}$ As $_{4}$

arXiv:2302.04717 · doi:10.1103/PhysRevB.107.134511

Abstract

Members of the CaK(Fe $_{1 - x}$ Cr $_{x}$ ) $_{4}$ As $_{4}$ series have been synthesized by high-temperature solution growth in single crystalline form and characterized by X-ray diffraction, elemental analysis, magnetic and transport measurements. The effects of Cr substitution on the superconducting and magnetic ground states of CaKFe $_{4}$ As $_{4}$ ( $T_{c}$ = 35 K) have been studied. These measurements show that the superconducting transition temperature decreases monotonically and is finally suppressed below 1.8 K as $x$ is increased from 0 to 0.038. The magnetic transition temperature increases in a roughly linear manner as Cr substitution increases. A temperature-composition (\textit{T}-\textit{x}) phase diagram is constructed, revealing a half-dome of superconductivity with the magnetic transition temperature, $T^{*}$ , appearing near 22~K for $x$ $\sim$ 0.017 and rising slowly up to 60~K for $x$ $\sim$ 0.077. The $T$ - $x$ phase diagrams for CaK(Fe $_{1 - x}$ $T$ $_{x}$ ) $_{4}$ As $_{4}$ for $T$ = Cr and Mn are essentially the same despite the nominally different band filling; this is in marked contrast to $T$ = Co and Ni series for which the $T$ - $x$ diagrams scale by a factor of two, consistent with the different changes in band filling Co and Ni would produce when replacing Fe. Superconductivity of CaK(Fe $_{1 - x}$ Cr $_{x}$ ) $_{4}$ As $_{4}$ is also studied as a function of magnetic field. A clear change in $H_{c 2}^{'}$ ( $T$ )/ $T_{c}$ , where $H_{c 2}^{'}$ ( $T$ ) is d $H_{c 2}$ ( $T$ )/d $T$ , at $x$ $\sim$ 0.012 is observed and probably is related to change of the Fermi surface due to magnetic order. Coherence length and the London penetration depths are also calculated based on $H_{c 1}$ and $H_{c 2}$ data. Coherence lengths as the function of $x$ also shows changes near $x$ = 0.012, again consistent with Fermi surfaces changes associated with the magnetic ordering seen for higher $x$ -values.

This work uses the same synthesis and measurements methods to systematicly analysis Cr1144 as our previous work arXiv:2204.10925 (existence of the text overlap) but gives the clear proof of the bi-modal response to electron and hole doping in Fe-based superconductors

Superconductivity and magnetic and transport properties of single-crystalline CaK(Fe1−x​Crx​)4​As4​

Abstract

References in corpus (7)

Superconductivity and magnetic and transport properties of single-crystalline CaK(Fe $_{1 - x}$ Cr $_{x}$ ) $_{4}$ As $_{4}$