Two first-order phase transitions of the valence-fluctuating compound EuPtP at T1 =246K and T2 =200K were examined by means of resonant x-ray diffraction at the Eu L3 absorption edge. Although previous Mössbauer spectroscopy and preliminary x-ray diffraction experiments have suggested charge-ordered states, characteristic energy spectra of the 111 and 11 2/3 reflections observed in the present experiment unambiguously indicated that twofold and threefold superstructures of Eu valence exist below T2 and between T1 and T2, respectively. We also propose a mechanism to explain the charge ordering in EuPtP based on a charge-lattice coupling that alters a Coulomb repulsion.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||出版済み - 11月 30 2010|
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