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Article
Non-Fermi-liquid behaviors associated with a magnetic quantum-critical point in Sr(Co{1-x}Ni{x})2As2 single crystals
arXiv
  • Nediadath S. Sangeetha, Ames Laboratory
  • Lin-Lin Wang, Ames Laboratory
  • Andrei V. Smirnov, Ames Laboratory
  • Volodymyr Smetana, Stockholm University
  • A.-V. Mudring, Stockholm University
  • Duane D. Johnson, Iowa State University and Ames Laboratory
  • Makariy A. Tanatar, Iowa State University and Ames Laboratory
  • Ruslan Prozorov, Iowa State University and Ames Laboratory
  • David C. Johnston, Iowa State University and Ames Laboratory
Document Type
Article
Publication Version
Submitted Manuscript
Publication Date
1-1-2019
Abstract

Electron-doped Sr(Co{1-x}Ni{x})2As2 single crystals with compositions x = 0 to 0.9 were grown out of self-flux and SrNi2As2 single crystals out of Bi flux. The crystals were characterized using single-crystal x-ray diffraction (XRD), magnetic susceptibility chi(H,T), isothermal magnetization M(H,T), heat capacity Cp(H,T), and electrical resistivity ho(H,T) measurements versus applied magnetic field H and temperature T. The chi(T) data show that the crystals exhibit an antiferromagnetic (AFM) ground state almost immediately upon Ni doping on the Co site. Ab-initio electronic-structure calculations for x = 0 and x = 0.15 indicate that a flat band with a peak in the density of states just above the Fermi energy is responsible for this initial magnetic-ordering behavior on Ni doping. The Curie-Weiss-like T dependence of \chi in the paramagnetic (PM) state indicates dominant ferromagnetic (FM) interactions. The small ordered moments ~0.1 muB per transition metal atom and the values of the Rhodes-Wohlfarth ratio indicate that the magnetism is itinerant. The Cp(T) at low T exhibits Fermi-liquid behavior for 0 < x < 0.15 whereas an evolution to a logarithmic non-Fermi-liquid (NFL) behavior is found for x = 0.2 to 0.3. The logarithmic dependence is suppressed in an applied magnetic field. The low- T rho(H = 0,T) data show a T^2 dependence for 0 < x < 0.20 and a power-law dependence with n < 2 for x = 0.20 and 0.30. These low-T NFL behaviors observed in the Cp and rho measurements are most evident near the quantum-critical concentration x ~ 0.3 at which a T = 0 composition-induced transition from the AFM phase to the PM phase occurs.

Comments

This is a pre-print of the article Sangeetha, N. S., L. L. Wang, A. V. Smirnov, V. Smetana, A-V. Mudring, D. D. Johnson, M. A. Tanatar, R. Prozorov, and D. C. Johnston. "Non-Fermi-liquid behaviors associated with a magnetic quantum-critical point in Sr (Co {1-x} Ni {x}) 2As2 single crystals." arXiv preprint arXiv:1907.08238 (2019). Posted with permission.

Copyright Owner
The Authors
Language
en
File Format
application/pdf
Citation Information
Nediadath S. Sangeetha, Lin-Lin Wang, Andrei V. Smirnov, Volodymyr Smetana, et al.. "Non-Fermi-liquid behaviors associated with a magnetic quantum-critical point in Sr(Co{1-x}Ni{x})2As2 single crystals" arXiv (2019)
Available at: http://works.bepress.com/duane_johnson/139/