Crystallographic phase transition and high-Tc superconductivity in LaFeAsO:F

T. Nomura, S. W. Kim, Y. Kamihara, M. Hirano, P. V. Sushko, K. Kato, M. Takata, A. L. Shluger, H. Hosono

Research output: Contribution to journalArticlepeer-review

208 Citations (Scopus)

Abstract

Undoped LaFeAsO, the parent compound of the newly found high-Tc superconductor, exhibits a sharp decrease in the temperature-dependent resistivity at ∼160K. The anomaly can be suppressed by F doping with simultaneous appearance of superconductivity appears correspondingly, suggesting a close association of the anomaly with the superconductivity. We examined the crystal structures, magnetic properties and conductivity of undoped (normal conductor) and 14at.% F-doped LaFeAsO (Tc = 20K) by synchrotron x-ray diffraction (XRD), DC magnetic measurements, and abinitio calculations demonstrated that the anomaly is associated with a phase transition from tetragonal (P4/nmm) to orthorhombic (Cmma) phases at ∼160K as well as an antiferromagnetic spin ordering transition at ∼140K. These transitions can be explained by spin configuration-dependent potential energy surfaces derived from the abinitio calculations. The suppression of the transitions is ascribed to interrelated effects of geometric and electronic structural changes due to doping by F- ions.

Original languageEnglish
Article number125028
JournalSuperconductor Science and Technology
Volume21
Issue number12
DOIs
Publication statusPublished - 2008 Dec 1

ASJC Scopus subject areas

  • Ceramics and Composites
  • Condensed Matter Physics
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry

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