Effect of Co doping and hydrostatic pressure on SrFe₂ As₂

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• 作者：E. Lengyel ; M. Kumar ; W. Schnelle ; A. Leithe-Jasper and M. Nicklas
• 刊名：physica status solidi (b)
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：254
• 期：1
• 全文大小：740K
• ISSN：1521-3951

文摘

We report a pressure study on electron doped SrFe2−xCoxAs2 by electrical-resistivity (ρ) and magnetic-susceptibility (χ) experiments. Application of either external pressure or Co substitution rapidly suppresses the spin-density wave ordering of the Fe moments and induces superconductivity in SrFe2As2. At x=0.2 the broad superconducting (SC) dome in the T−−p phase diagram exhibits its maximum Tc,max=20K at a pressure of only pmax≈0.75GPa. In SrFe1.5Co0.5As2 no superconductivity is observed anymore up to 2.8 GPa. Upon increasing the Co concentration the maximum of the SC dome shifts toward lower pressure accompanied by a decrease in the value of Tc,max. Even though, superconductivity is induced by both tuning methods, Co substitution leads to a much more robust SC state. Our study evidences that in SrFe2−xCoxAs2 both, the effect of pressure and Co substitution, have to be considered in order to understand the SC phase-diagram and further attests the close relationship of SrFe2As2 and its sister compound BaFe2As2.