In this paper we report a detailed $\mu^{+}$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.

Giacomo Prando, Samuele Sanna, Gianrico Lamura, Toni Shiroka, Matteo Tropeano, Andrea Palenzona, et al. (2013). Phase separation at the magnetic-superconducting transition in La0.7Y0.3FeAsO1-xFx. PHYSICA STATUS SOLIDI. A, APPLICATIONS AND MATERIALS SCIENCE, 250(3), 599-602 [10.1002/pssb.201200767].

Phase separation at the magnetic-superconducting transition in La0.7Y0.3FeAsO1-xFx

SANNA, SAMUELE;
2013

Abstract

In this paper we report a detailed $\mu^{+}$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.
2013
Giacomo Prando, Samuele Sanna, Gianrico Lamura, Toni Shiroka, Matteo Tropeano, Andrea Palenzona, et al. (2013). Phase separation at the magnetic-superconducting transition in La0.7Y0.3FeAsO1-xFx. PHYSICA STATUS SOLIDI. A, APPLICATIONS AND MATERIALS SCIENCE, 250(3), 599-602 [10.1002/pssb.201200767].
Giacomo Prando; Samuele Sanna; Gianrico Lamura; Toni Shiroka; Matteo Tropeano; Andrea Palenzona; Hans-Joachim Grafe; Bernd Buchner; Pietro Carretta; ...espandi
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/549483
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 7
  • ???jsp.display-item.citation.isi??? 7
social impact