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Incommensurate spin correlations in highly oxidized cobaltates La(2−x)Sr(x)CoO(4)

We observe quasi-static incommensurate magnetic peaks in neutron scattering experiments on layered cobalt oxides La(2−x)Sr(x)CoO(4) with high Co oxidation states that have been reported to be paramagnetic. This enables us to measure the magnetic excitations in this highly hole-doped incommensurate r...

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Detalles Bibliográficos
Autores principales: Li, Z. W., Drees, Y., Kuo, C. Y., Guo, H., Ricci, A., Lamago, D., Sobolev, O., Rütt, U., Gutowski, O., Pi, T. W., Piovano, A., Schmidt, W., Mogare, K., Hu, Z., Tjeng, L. H., Komarek, A. C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4846828/
https://www.ncbi.nlm.nih.gov/pubmed/27117928
http://dx.doi.org/10.1038/srep25117
Descripción
Sumario:We observe quasi-static incommensurate magnetic peaks in neutron scattering experiments on layered cobalt oxides La(2−x)Sr(x)CoO(4) with high Co oxidation states that have been reported to be paramagnetic. This enables us to measure the magnetic excitations in this highly hole-doped incommensurate regime and compare our results with those found in the low-doped incommensurate regime that exhibit hourglass magnetic spectra. The hourglass shape of magnetic excitations completely disappears given a high Sr doping. Moreover, broad low-energy excitations are found, which are not centered at the incommensurate magnetic peak positions but around the quarter-integer values that are typically exhibited by excitations in the checkerboard charge ordered phase. Our findings suggest that the strong inter-site exchange interactions in the undoped islands are critical for the emergence of hourglass spectra in the incommensurate magnetic phases of La(2−x)Sr(x)CoO(4).