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Type: Artigo de periódico
Title: Collective phase-like mode and the role of lattice distortions at T-N similar to T-C in RMn2O5 (R = Pr, Sm, Gd, Tb, Bi)
Author: Massa, NE
Garcia-Flores, AF
Meneses, DD
del Campo, L
Echegut, P
Fabbris, GFL
Martinez-Lope, MJ
Alonso, JA
Abstract: We report on electronic collective excitations in RMn2O5 (R = Pr, Sm, Gd, Tb) showing condensation starting at and below similar to T-N similar to T-C similar to 40-50 K. Their origin is understood as partial delocalized e(g) electron orbitals in the Jahn-Teller distortion of the pyramid dimer with strong hybridized Mn3+-O bonds. Our local probes, Raman, infrared, and x-ray absorption, back the conclusion that there is no structural phase transition at T-N similar to T-C. Ferroelectricity is magnetically assisted by electron localization triggering lattice polarizability by unscreening. We have also found phonon hardening as the rare earth is sequentially replaced. This is understood as a consequence of lanthanide contraction. It is suggested that partially f-electron screened rare earth nuclei might be introducing a perturbation to eg electrons prone to delocalize as the superexchange interaction takes place.
Country: Inglaterra
Editor: Iop Publishing Ltd
Citation: Journal Of Physics-condensed Matter. Iop Publishing Ltd, v. 24, n. 19, 2012.
Rights: fechado
Identifier DOI: 10.1088/0953-8984/24/19/195901
Date Issue: 2012
Appears in Collections:Unicamp - Artigos e Outros Documentos

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