The local structure of La(Fe1-xMnx)AsO, showing suppression of long-range magnetic order by Mn-substitution, has been studied. Extended X-ray absorption fine structure (EXAFS) measurements at As K-edge and Fe K-edge are used to probe the atomic correlations in the FeAs-layer. We have found that both Fe-As and Fe-Fe bondlengths tend to increase with increasing Mn concentration. The associated mean square relative displacements (MSRD) reveal a gradual increase indicating increased local disorder in the FeAs-layer with Mn content. The results reveal that the FeAs-layer thickness, measured by the As-height (hAs) from the Fe-Fe plane, is correlated with the Néel temperature. Furthermore, Fe Kβ X-ray emission spectroscopy (XES) shows a sharp increase in the Fe local magnetic moment with Mn substitution. The importance of the FeAs layer thickness in describing magnetic correlations in La(Fe1−xMnx)AsO is discussed.
The local structure and magnetic correlations in La(Fe1-Mn )AsO system
Provino, A.;Lamura, G.;Martinelli, A.;Manfrinetti, P.;Putti, M.;
2019-01-01
Abstract
The local structure of La(Fe1-xMnx)AsO, showing suppression of long-range magnetic order by Mn-substitution, has been studied. Extended X-ray absorption fine structure (EXAFS) measurements at As K-edge and Fe K-edge are used to probe the atomic correlations in the FeAs-layer. We have found that both Fe-As and Fe-Fe bondlengths tend to increase with increasing Mn concentration. The associated mean square relative displacements (MSRD) reveal a gradual increase indicating increased local disorder in the FeAs-layer with Mn content. The results reveal that the FeAs-layer thickness, measured by the As-height (hAs) from the Fe-Fe plane, is correlated with the Néel temperature. Furthermore, Fe Kβ X-ray emission spectroscopy (XES) shows a sharp increase in the Fe local magnetic moment with Mn substitution. The importance of the FeAs layer thickness in describing magnetic correlations in La(Fe1−xMnx)AsO is discussed.File | Dimensione | Formato | |
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