Coexistence of superconductivity and magnetism in CaK(Fe<sub>1-x</sub>Ni<sub>x</sub>)<sub>4</sub>As<sub>4</sub> as probed by <sup>57</sup>Fe Mössbauer spectroscopy
ORAL
Abstract
Temperature dependent 57Fe Mössbauer spectroscopy and specific heat measurements for CaK(Fe1-xNix)4As4 with x = 0, 0.017, 0.033, and 0.049 are presented. No magnetic hyperfine field (i.e. no static magnetic order) was detected down to 5.5 K for x = 0 and 0.017 in agreement with the absence of any additional feature below superconducting transition temperature, Tc, in the specific heat data. The evolution of magnetic hyperfine field with temperature was studied for x = 0.033 and 0.049. The long-range magnetic order in these two compounds coexists with superconductivity. The magnetic hyperfine field, Bhf, (ordered magnetic moment) below Tc in CaK(Fe0.967Ni0.033)4As4 is continuously suppressed with the developing superconducting order parameter. The Bhf(T) data for CaK(Fe0.967Ni0.033)4As4, and CaK(Fe0.951Ni0.049)4As4 can be described by Machida's model for coexistence of itinerant spin density wave magnetism and superconductivity [K. Machida, J. Phys. Soc. Jpn. 50, 2195 (1981)].
*This work was supported by the U.S. DOE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Contract No. DE-AC02-07CH11358. W. R. M. was supported by the Gordon and Betty Moore Foundation’s EPiQS Initiative through Grant No. GBMF4411
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Presenters
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Sergey Budko
- Iowa State University
- Department of Physics, Iowa State University, Ames Laboratory, Ames, Iowa 50011, USA
- Ames Laboratory, Iowa State University
- Ames Laboratory/Iowa State University
- Ames Laboratory and Dept. of Phys. and Astro.,, Iowa State Univ.
- Ames Laboratory and Department of Physics & Astronomy, Iowa State University, Ames, IA 50010, USA
- Ames Lab & Dept of Physics and Astronomy, Iowa State University
- Physics, Iowa State University/Ames Laboratory
- Iowa State University and Ames Laboratory