Iron niobates, pure and substituted with copper (FeCuNbO with x = 0-0.15), were prepared by the solid-state method and characterized by X-ray diffraction, Raman spectroscopy, and magnetic measurements. The results of the structural characterizations revealed the high solubility of Cu ions in the structure and better structural stability compared to the pure sample. The analysis of the magnetic properties showed that the antiferromagnetic-ferromagnetic transition was caused by the insertion of Cu ions into the FeNbO structure. The pure FeNbO structure presented an antiferromagnetic ordering state, with a Néel temperature of approximately 36.81K. The increase in substitution promoted a change in the magnetic ordering, with the state passing to a weak ferromagnetic order with a transition temperature (T) higher than the ambient temperature. The origin of the ferromagnetic ordering could be attributed to the increase in super-exchange interactions between Fe/Cu ions in the Cu-O-Fe chains and the formation of bound magnetic polarons in the oxygen vacancies.
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http://dx.doi.org/10.3390/ma15217424 | DOI Listing |
Dalton Trans
December 2023
Faculty of Electrical Engineering and Computer Science & MANSiD Research Center, Stefan cel Mare University, 13 Universitatii St, 720229, Suceava, Romania.
In the present study, the effect of heterovalent Fe ions on the dielectric, pyroelectric, and ferroelectric properties of the (1 - )AgNbO-FeNbO ( = 0.005, 0.01, 0.
View Article and Find Full Text PDFChem Commun (Camb)
November 2023
Institute for Energy Research, Jiangsu University, Zhenjiang 212013, P. R. China.
High capacity and outstanding rate performance of the FeNbO nanochain anode with both intercalation and conversion reactions for lithium-ion batteries are demonstrated. The unique one-dimensional structure and intercalation pseudocapacitive behavior of FeNbO accelerate the reaction kinetics. X-ray diffractometer measurement confirms a five-electron transfer mechanism for Li storage.
View Article and Find Full Text PDFMaterials (Basel)
April 2023
I3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal.
In this work, iron niobate (FeNbO) was prepared via two processes based on the sol-gel method: colloidal gel and polymeric gel. The obtained powders were submitted to heat treatments at different temperatures based on the results obtained via differential thermal analysis. The structures of the prepared samples were characterized via X-ray diffraction and the morphology was characterized via scanning electron microscopy.
View Article and Find Full Text PDFPhys Chem Chem Phys
March 2023
School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
ABO-type materials have shown significant potential for applications as luminescence and photocatalytic materials, and the orthorhombic FeNbO (-FeNbO) material has also shown excellent promise in catalytic electrodes, unlike other common ABO materials. However, little computational work has been carried out on the -FeNbO structure, potentially because it is disordered and thus not straightforward to simulate. In this work, we first confirmed the accuracy of the force field parameters obtained from previous studies through optimizations carried out using the GULP code.
View Article and Find Full Text PDFMaterials (Basel)
October 2022
Department of Physics, Federal University of Sergipe, São Cristóvão 49100-000, Brazil.
Iron niobates, pure and substituted with copper (FeCuNbO with x = 0-0.15), were prepared by the solid-state method and characterized by X-ray diffraction, Raman spectroscopy, and magnetic measurements. The results of the structural characterizations revealed the high solubility of Cu ions in the structure and better structural stability compared to the pure sample.
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