Concentration dependence of magnetic moment in Ce1-xFexO2

Abstract

In this study, we examined the impact of iron doping on the structural, chemical, and magnetic properties of ceria (Ce 1-x Fe x O 2 ). Samples were produced in triplicate through a coprecipitation approach in a forced hydrolysis synthesis that yielded consistently sized nanocrystals, using three different cerium precursors: cerium chloride, cerium ammonium nitrate and cerium nitrate. Particles were characterized by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR) spectroscopy and vibrating sample magnetometry (VSM). XRD showed the average crystallite size to be 4.4 ± 1.2 nm, which agreed well with TEM data. XPS and EPR data shows iron to be in the Fe 3+ state and confirms the nominal dopant concentration. The moment per Fe ion found was largest at the lowest dopant concentrations, with values of 0.078 and 0.055 µ B /Fe ion for 0.1 and 0.5% Fe, respectively, which quickly decreased as the concentration was increased. We used XPS to estimate Ce 3+ /Ce 4+ ratio to be in the 0.2-0.3 range and observed a linear relation between the saturation magnetization and the Ce 3+ /Ce 4+ ratio.Introduction:

Kinetics Study of Photocatalytic Activity of Flame-Made Unloaded and Fe-Loaded CeO2Nanoparticles

“…These observations could be ascribed to partial substitution of Ce 4+ ions (0.101 nm) by Fe 3+ ions (0.064 nm) [41]. A decrease of unit cell parameters due to the substitution of larger ion by the smaller one was also found in previous reports [42,43].…”

Study of the relation between oxygen vacancies and ferromagnetism in Fe-doped TiO2 nano-powders

“…Similar results were reported in many others Fe doped O-DMS. [45][46][47][48] The fact that M decreases with iron concentration rules out the possibility of ferromagnetism coming from iron precipitation. Ms is smaller than that expected for Fe 2þ or Fe 3þ indicating that only a small fraction of the Fe dopants participates in the observed ferromagnetism.…”

Strain-Engineered Cube Nanocrystals Ce1–yFeyO2 That Brought Forth Abnormal Structural and Magnetic Properties

“…For the present system, there are sufficient OH groups because of the high alkalinity (pH > 14). By contrast, when Fe 3+ -doped CeO 2 was prepared using other methodologies (e.g., coprecipitation, − combustion, , or electrochemical deposition), cube shape cannot be obtained but smaller rounded grains (<10 nm).…”

“…As demonstrated in Figure 4, there are three striking trends: (i) the lattice of current cube nanostructures Ce 1−y Fe y O 2 was heavily contracted with doping (Figure 4a), showing lattice parameters much smaller than those reported for CeO 2 -based solid solutions with other dopants; (ii) as indicated in Figure 4b, the lattice dimension for current nanocubes was also smaller than those for rounded grains previously reported in the literature at the same doping of Fe 3+ when prepared using other methods; and (iii) the lattice contraction for nanocubes obeys a linear relationship below the solubility limit (i.e., y < 0.15), as represented by the red line in Figure 4b. Above the solubility limit, the lattice dimension for nanocubes deviated from the Lattice parameters for Fe 3+ -doped CeO 2 rounded grains prepared by coprecipitation 32,33 and the combustion method 34,35 are also given for comparison. Solid line represents the linear data fit result for current nanocubes in terms of eq 1 at y < 0.15, while the dotted line denotes data when calculated from eq 4.…”

“…(a) Comparisons of lattice parameters for Ce 1– y Fe y O 2 nanocubes with those reported in the literature − for CeO 2 doped by other ions (e.g., Nd 3+ , Pb 2+ , Bi 3+ , Co 2+ , Er 3+ , Mn 3+ , and Cu 2+ ), and (b) dopant level dependence of lattice parameters for cube nanostructures Ce 1– y Fe y O 2 . Lattice parameters for Fe 3+ -doped CeO 2 rounded grains prepared by coprecipitation , and the combustion method , are also given for comparison. Solid line represents the linear data fit result for current nanocubes in terms of eq at y < 0.15, while the dotted line denotes data when calculated from eq .…”