Phase separation at the magnetic-superconducting transition in La$_{0.7}$Y$_{0.3}$FeAsO$_{1-x}$F$_{x}$

G. Prando; S. Sanna; G. Lamura; T. Shiroka; M. Tropeano; A. Palenzona; H. -J. Grafe; B. Büchner; P. Carretta; R. De Renzi

doi:10.1002/pssb.201200767

paper

Phase separation at the magnetic-superconducting transition in La $_{0.7}$ Y $_{0.3}$ FeAsO $_{1 - x}$ F $_{x}$

arXiv:1209.6512 · doi:10.1002/pssb.201200767

Abstract

In this paper we report a detailed $μ^{+}$ SR and {} $^{19}$ F-NMR study of the La $_{0.7}$ Y $_{0.3}$ FeAsO $_{1 - x}$ F $_{x}$ class of materials. Here, the diamagnetic La $_{1 - y}$ Y $_{y}$ substitution increases chemical pressure and, accordingly, sizeably enhances the optimal superconducting transition temperature. We investigate the magnetic-superconducting phase transition by keeping the Y content constant ( $y = 0.3$ ) and by varying the F content in the range $0.025 \leq x \leq 0.15$ . Our results show how magnetism and superconductivity coexist for $x = 0.065$ . Such coexistence is due to segregation of the two phases in macroscopic regions, resembling what was observed in LaFeAsO $_{1 - x}$ F $_{x}$ materials under applied hydrostatic pressure. This scenario is qualitatively different from the nanoscopic coexistence of the two order parameters observed when La is fully substituted by magnetic rare-earth ions like Sm or Ce.

Proceedings of QCNP12 Conference

Phase separation at the magnetic-superconducting transition in La $_{0.7}$ Y $_{0.3}$ FeAsO $_{1 - x}$ F $_{x}$

Abstract

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Phase separation at the magnetic-superconducting transition in La0.7​Y0.3​FeAsO1−x​Fx​

Abstract

References in corpus (8)

Cited by in corpus (2)

Phase separation at the magnetic-superconducting transition in La $_{0.7}$ Y $_{0.3}$ FeAsO $_{1 - x}$ F $_{x}$