Enhancing the stabilization of nanostructured rocksalt-like high entropy oxide by Gd addition

• Published in: Materials letters Vol. 285; p. 129175
• Main Authors: Cardoso, André L.F., Perdomo, Claudia P.F., Kiminami, Ruth H.G.A., Gunnewiek, Rodolfo F.K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.02.2021; Elsevier BV
• Subjects: Crystal lattices; Crystallites; Entropy; Fast synthesis; Gadolinium; Gd2O3; High entropy ceramic; Materials science; Nanostructure; Oxidation; Polymeric solution method; Raman spectroscopy; Valence; Polymeric solution method; Nanostructure; Fast synthesis; High entropy ceramic; Gd2O3
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2020.129175

[Display omitted] •Nanostructured single phase high entropy oxide (HEOx) was easily synthesized by a fast polymeric solution method.•Gadolinium enhanced the stabilization of rocksalt-type HEOx.•With Gd, the diffusion of copper to the lattice increased.•The configurational entropy increased with the addition of Gd3+ (Sconfig = 1.73R).•Gadolinium also prevented the excessive crystallite growth. In this work, nanostructured single phase high entropy oxide was easily synthesized by a fast polymeric solution method. Despite the higher ionic radius, coordination and oxidation state, gadolinium was homogeneously distributed in crystallites. Their effect on the lattice was studied by Raman spectroscopy, transmission electron microscopy and X-ray diffraction. The configurational entropy increased with the addition of Gd3+, but the expansion in the lattice is mostly associated to the diffusion of copper to the crystal. However, gadolinium enhances the asymmetry on longitudinal-optic (A1g) Raman mode and also prevents the excessive growth of crystallites.