Disorder-driven electronic localization and phase separation in superconducting Fe1+yTe0.5Se0.5 single crystals

S. Rößler, Dona Cherian, S. Harikrishnan, H. L. Bhat, Suja Elizabeth, J. A. Mydosh, L. H. Tjeng, F. Steglich, and S. Wirth
Phys. Rev. B 82, 144523 – Published 22 October 2010

Abstract

We have investigated the influence of Fe excess on the electrical transport and magnetism of Fe1+yTe0.5Se0.5 (y=0.04 and 0.09) single crystals. Both compositions exhibit resistively determined superconducting transitions (Tc) with an onset temperature of about 15 K. From the width of the superconducting transition and the magnitude of the lower critical field Hc1, it is inferred that excess of Fe suppresses superconductivity. The linear and nonlinear responses of the ac susceptibility show that the superconducting state for these compositions is inhomogeneous. A possible origin of this phase separation is a magnetic coupling between Fe excess occupying interstitial sites in the chalcogen planes and those in the Fe-square lattice. The temperature derivative of the resistivity dρ/dT in the temperature range Tc<T<Ta with Ta being the temperature of a magnetic anomaly, changes from positive to negative with increasing Fe. A log1/T divergence of the resistivity above Tc in the sample with higher amount of Fe suggests a disorder-driven electronic localization.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 14 July 2010

DOI:https://doi.org/10.1103/PhysRevB.82.144523

©2010 American Physical Society

Authors & Affiliations

S. Rößler1,*, Dona Cherian2, S. Harikrishnan2, H. L. Bhat2,3, Suja Elizabeth2, J. A. Mydosh4, L. H. Tjeng1, F. Steglich1, and S. Wirth1

  • 1Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany
  • 2Department of Physics, Indian Institute of Science, C.V. Raman Avenue, Bangalore 560012, India
  • 3Centre for Liquid Crystal Research, Jalahalli, Bangalore 560013, India
  • 4Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands

  • *roessler@cpfs.mpg.de

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 82, Iss. 14 — 1 October 2010

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×