1. Temperature-Dependent As K-Edge EXAFS Studies of LaFe 1−x Co x AsO (x = 0.0 and 0.11) Single Crystals
- Author
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Valentin G. Ivanov, A. A. Ivanov, Boby Joseph, Antonio Bianconi, Alessandro Ricci, Naurang L. Saini, Nicola Poccia, and Alexey P. Menushenkov
- Subjects
Materials science ,Fe-As bond correlations ,FOS: Physical sciences ,Fe based superconductors ,02 engineering and technology ,01 natural sciences ,Thermal expansion ,Superconductivity (cond-mat.supr-con) ,Tetragonal crystal system ,0103 physical sciences ,optical and magnetic materials ,010306 general physics ,Superconductivity ,Condensed matter physics ,Extended X-ray absorption fine structure ,Condensed Matter - Superconductivity ,electronic ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Magnetic susceptibility ,Electronic, Optical and Magnetic Materials ,EXAFS ,K-edge ,local structure ,Orthorhombic crystal system ,Anomaly (physics) ,0210 nano-technology ,condensed matter physics - Abstract
We report the experimental results of temperature dependent polarized As K-edge extended x-ray absorption fine structure (EXAFS) of LaFe1-xCoxAsO (x=0.0 and 0.11) single-crystals. By aligning the Fe-As bond direction in the direction of the x-ray beam polarization we have been able to identify an anomaly in the Fe-As bond correlations at the tetragonal to orthorhombic transition at 150K, while previous investigations with standard unpolarized EXAFS of undoped LaFeAsO powder samples were not able to detect any such anomaly. Using our approach we have been able to identify in the superconducting doped sample, LaFe0.89Co0.11AsO, a broad anomaly around 60 K. The low temperature anomaly has good correlations with the temperature dependence of several properties like resistivity, magnetic susceptibility, linear thermal expansion, etc indicating the emergence of the dynamical oscillations of the Fe - As pairs, 7 pages, 3 figures
- Published
- 2016