Document Type

Article

Publication Date

3-15-2011

Journal or Book Title

Physical Review B

Volume

83

First Page

094520

DOI

10.1103/PhysRevB.83.094520

Abstract

We report magnetic susceptibility, resistivity, and heat capacity measurements on single crystals of the Sr(Fe1−xCox)2As2 and Sr1−yEuy(Fe0.88Co0.12)2As2 series. The optimal Co concentration for superconductivity in Sr(Fe1−xCox)2As2 is determined to be x~0.12. On the basis of this, we grew members of the Sr1−yEuy(Fe0.88Co0.12)2As2 series so as to examine the effects of well-defined, local magnetic moments on the superconducting state. We show that superconductivity is gradually suppressed by paramagnetic Eu2+ doping and coexists with antiferromagnetic ordering of Eu2+ as long as Tc>TN. For y⩾0.65, TN crosses Tc and the superconducting ground state (as manifested by zero resistivity) abruptly disappears with evidence for competition between superconductivity and local moment antiferromagnetism for y up to 0.72. It is speculated that the suppression of the antiferromagnetic fluctuations of the Fe sublattice by coupling to the long-range order of the Eu2+ sublattice destroys bulk superconductivity when TN>Tc.

Comments

This article is from Physical Review B 83 (2011): 094520, doi:10.1103/PhysRevB.83.094520. Posted with permission.

Copyright Owner

American Physical Society

Language

en

File Format

application/pdf

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