Spin-orbit-induced mixed-spin ground state in RNiO₃ perovskites probed by x-ray absorption spectroscopy: Insight into the metal-to-insulator transition

We report on a Ni L<sub>2,3</sub> edge x-ray absorption spectroscopy study in RNiO₃ perovskites. These compounds exhibit a metal-to-insulator (MI) transition as temperature decreases. The L₃ edge presents a clear splitting in the insulating state, associated to a less hybridized ground s...

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Detalles Bibliográficos
Autores principales: Piamonteze, Cinthia, Groot, F. M. F. de, Tolentino, Hélio C. N., Ramos, A. Y., Massa, Néstor Emilio, Alonso, José Antonio, Martínez Lope, María Jesús
Formato: Articulo
Lenguaje:Inglés
Publicado: 2005
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/126591
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Sumario:We report on a Ni L<sub>2,3</sub> edge x-ray absorption spectroscopy study in RNiO₃ perovskites. These compounds exhibit a metal-to-insulator (MI) transition as temperature decreases. The L₃ edge presents a clear splitting in the insulating state, associated to a less hybridized ground state. Using charge transfer multiplet calculations, we establish the importance of the crystal field and 3d spin-orbit coupling to create a mixed-spin ground state. We explain the MI transition in RNiO₃ perovskites in terms of modifications in the Ni³⁺ crystal field splitting that induces a spin transition from an essentially low-spin to a mixed-spin state.