Metal-insulator transition in Nd$_{1-x}$Eu$_{x}$NiO$_{3}$ compounds

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dc.creatorEscote, M. T.
dc.creatorBarbeta, V. B.
dc.creatorJardim, R. F.
dc.creatorCampo, J.
dc.date2006-06-22
dc.date.accessioned2026-07-07T07:52:43Z
dc.date.available2026-07-07T07:52:43Z
dc.descriptionPolycrystalline Nd$_{1-x}$Eu$_{x}$NiO$_3$ ($0 \leq x \leq 0.5$) compounds were synthesized in order to investigate the character of the metal-insulator (MI) phase transition in this series. Samples were prepared through the sol-gel route and subjected to heat treatments at $\sim$1000 $^\circ$C under oxygen pressures as high as 80 bar. X-ray Diffraction (XRD) and Neutron Powder Diffraction (NPD), electrical resistivity $ρ(T)$, and Magnetization $M(T)$ measurements were performed on these compounds. The results of NPD and XRD indicated that the samples crystallize in an orthorhombic distorted perovskite structure, space group $Pbnm$. The analysis of the structural parameters revealed a sudden and small expansion of $\sim$0.2% of the unit cell volume when electronic localization occurs. This expansion was attributed to a small increase of $\sim$0.003 Å of the average Ni-O distance and a simultaneous decrease of $\sim$$- 0.5^\circ$ of the Ni-O-Ni superexchange angle. The $ρ(T)$ measurements revealed a MI transition occurring at temperatures ranging from $T_{\rm MI}\sim 193$ to 336 K for samples with $x = 0$ and 0.50, respectively. These measurements also show a large thermal hysteresis in NdNiO$_{3}$ during heating and cooling processes suggesting a first-order character of the phase transition at $T_{\rm MI}$. The width of this thermal hysteresis was found to decrease appreciably for the sample Nd$_{0.7}$Eu$_{0.3}$NiO$_{3}$. The results indicate that cation disorder associated with increasing substitution of Nd by Eu is responsible for changing the first order character of the transition in NdNiO$_{3}$.
dc.description19 pages, 9 figures
dc.identifierhttps://arxiv.org/abs/cond-mat/0606573
dc.identifierhttp://arxiv.org/abs/cond-mat/0606573
dc.identifierJournal of Physics: Condensed Matter 18 (2006), 6117-6132
dc.identifierdoi:10.1088/0953-8984/18/26/030
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/125983
dc.subjectStrongly Correlated Electrons
dc.subjectMaterials Science
dc.titleMetal-insulator transition in Nd$_{1-x}$Eu$_{x}$NiO$_{3}$ compounds
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