Abstract
We report a systematic study of the influence of antiferromagnetic and ferromagnetic phases of Eu moments on the superconducting phase upon doping the As site by isovalent P, which essentially acts like chemical pressure on EuFeAs. Bulk superconductivity with transition temperatures of 22 and 28 K are observed for and 0.20 samples, respectively. The Eu ions order antiferromagnetically for , while bulk superconductivity coexists with Eu-antiferromagnetism for 0.13 . In contrast, a crossover is observed for whereupon the Eu ions order ferromagnetically and superconductivity is fully suppressed. Density-functional-theory-based calculations reproduce the observed experimental findings consistently. We discuss in detail the coexistence of superconductivity and magnetism in a tiny region of the phase space and comment on the competition of ferromagnetism and superconductivity in the title compound.
- Received 8 December 2010
DOI:https://doi.org/10.1103/PhysRevB.83.054511
©2011 American Physical Society