Similarly to the half-doped manganese oxides with perovskite structure like La0.5Ca0.5MnO3. the double perovskite compound NaMn7O12 contains an equal number of Mn3+ and Mn4+ ions in the corner-sharing network of MnO6 octahedra and exhibits a CE order of the charge and spins of these ions at low temperature. Though, in NaMn7O12 the order is complete, the charge and spin ordering transitions are sharp and the system is free of disorder, phase coexistence or structural inhomogeneities thanks to the absence of chemical substitutions. Here we discuss two unusual features of the CE structure of NaMn7O12: (1) the e(g) 3d x(2)-y(2) orbital ordering expected from the direct crystallographic observation of compressed Mn3+O6 octa(2) the existence of a large amount of low-energy hedra below the charge ordering transition. excitations evidenced by the low temperature behavior of the specific heat. We propose a picture of nearly degenerate spin and orbital configurations of the CE structure arising from the peculiar orbital ordering.

Unusual e(g) 3d x(2)-y(2) orbital ordering and low-energy excitations in the CE structure of NaMn7O12 / Gauzzi, A; Gilioli, E; Prodi, A; Bolzoni, F; Licci, F; Marezio, M; Calestani, Gl; Affronte, Marco; Huang, Q; Santoro, A; Lynn, J.. - In: JOURNAL OF SUPERCONDUCTIVITY. - ISSN 0896-1107. - STAMPA. - 18:(2005), pp. 675-680. [10.1007/s10948-005-0057-3]

Unusual e(g) 3d x(2)-y(2) orbital ordering and low-energy excitations in the CE structure of NaMn7O12

AFFRONTE, Marco;
2005

Abstract

Similarly to the half-doped manganese oxides with perovskite structure like La0.5Ca0.5MnO3. the double perovskite compound NaMn7O12 contains an equal number of Mn3+ and Mn4+ ions in the corner-sharing network of MnO6 octahedra and exhibits a CE order of the charge and spins of these ions at low temperature. Though, in NaMn7O12 the order is complete, the charge and spin ordering transitions are sharp and the system is free of disorder, phase coexistence or structural inhomogeneities thanks to the absence of chemical substitutions. Here we discuss two unusual features of the CE structure of NaMn7O12: (1) the e(g) 3d x(2)-y(2) orbital ordering expected from the direct crystallographic observation of compressed Mn3+O6 octa(2) the existence of a large amount of low-energy hedra below the charge ordering transition. excitations evidenced by the low temperature behavior of the specific heat. We propose a picture of nearly degenerate spin and orbital configurations of the CE structure arising from the peculiar orbital ordering.
2005
18
675
680
Unusual e(g) 3d x(2)-y(2) orbital ordering and low-energy excitations in the CE structure of NaMn7O12 / Gauzzi, A; Gilioli, E; Prodi, A; Bolzoni, F; Licci, F; Marezio, M; Calestani, Gl; Affronte, Marco; Huang, Q; Santoro, A; Lynn, J.. - In: JOURNAL OF SUPERCONDUCTIVITY. - ISSN 0896-1107. - STAMPA. - 18:(2005), pp. 675-680. [10.1007/s10948-005-0057-3]
Gauzzi, A; Gilioli, E; Prodi, A; Bolzoni, F; Licci, F; Marezio, M; Calestani, Gl; Affronte, Marco; Huang, Q; Santoro, A; Lynn, J.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/2785
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