Publications by authors named "Marcelo A Macedo"

Herein, we carefully investigated the Fe doping effects on the structure and electron distribution of CrO nanoparticles using X-ray diffraction analysis (XRD), maximum entropy method (MEM), and density functional theory (DFT) calculations. We showed that increasing the Fe doping induces an enlargement in the axial ratio of /, which is associated with an anisotropic expansion of the unit cell. We found that as Fe replaces Cr in the CrO lattice, it caused a higher interaction between the metal 3 states and the oxygen 2 states, which led to a slight increase in the Cr/Fe-O1 bond length followed by an opposite effect for the Cr/Fe-O2 bonds.

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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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ZnO nanocrystals with three different morphologies have been synthesized via a simple sol-gel-based method using (bitter Amapá) and (sweet Amapá) latex as chelating agents. X-ray diffraction (XRD) and electron diffraction patterns (SAED) patterns showed the ZnO nanocrystals were a pure hexagonal wurtzite phase of ZnO. XRD-based spherical harmonics predictions and HRTEM images depicted that the nanocrystallites constitute pitanga-like (~15.

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Defect influences on the photoactivity of ZnO nanoparticles prepared by a powdered coconut water (ACP) assisted synthesis have been studied. The crystalline phase and morphology of ZnO nanoparticles were effectively controlled by adjusting the calcination temperature (400-700 °C). An induced transition of hybrid Zn(CO)(OH)/ZnO nanoparticles to single-phase ZnO nanoparticles was obtained at 480 °C.

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Resistive memories are considered the most promising candidates for the next generation of non-volatile memory; however, attention has so far been limited to rewritable memory features for applications in resistive random access memories (RRAM). In this article, we provide a new insight into the applicability of resistive memories. The characteristics of non-rewritable resistive memories (NRRM) were investigated.

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