TY - JOUR
T1 - Crystallographic phase transition and high-Tc superconductivity in LaFeAsO:F
AU - Nomura, T.
AU - Kim, S. W.
AU - Kamihara, Y.
AU - Hirano, M.
AU - Sushko, P. V.
AU - Kato, K.
AU - Takata, M.
AU - Shluger, A. L.
AU - Hosono, H.
N1 - Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.
PY - 2008/12/1
Y1 - 2008/12/1
N2 - 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.
AB - 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.
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U2 - 10.1088/0953-2048/21/12/125028
DO - 10.1088/0953-2048/21/12/125028
M3 - Article
AN - SCOPUS:58149520601
SN - 0953-2048
VL - 21
JO - Superconductor Science and Technology
JF - Superconductor Science and Technology
IS - 12
M1 - 125028
ER -