Exchange bias and magnetocrystalline anisotropy of non-stoichiometric CoxFe3−xO4 nanoparticles

Bangaru, Gokul; Matheswaran, P.; Pandian, Muthu Senthil; Paul, C. Arun; Ravikumar, K.; El‐Rehim, A. F. Abd

doi:10.1007/s10854-021-07606-7

Cited by 2 publications

(2 citation statements)

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“…In addition, nonstoichiometric spinel compounds also possess the potential for exhibiting different properties that have not been seen in their stoichiometric counterpart. For example, Gokul et al produced nonstoichiometric cobalt ferrite oxides and discovered field-dependent magnetizations that are different from either CoFe 2 O 4 or Fe 3 O 4 at 300 K …”

Section: Introductionmentioning

confidence: 99%

“…38 In addition, nonstoichiometric spinel compounds also possess the potential for exhibiting different properties that have not been seen in their stoichiometric counterpart. For example, Gokul et al produced nonstoichiometric cobalt ferrite oxides and discovered fielddependent magnetizations that are different from either CoFe 2 O 4 or Fe 3 O 4 at 300 K. 39 For the production of CoGa 2 O 4 , traditional synthesis methods usually require a precursor produced from electrodeposition, 32 chemical vapor deposition, 40 electrospinning, 29 or simple hydrothermal or solvothermal treatment, 31,34,35,41 followed by calcination conducted at 600−1000 °C for several hours. Such a calcination process favors the production of the thermodynamically stable phase of CoGa 2 O 4 ; however, it may cause the agglomeration of products.…”

Section: Introductionmentioning

confidence: 99%

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Supercritical Hydrothermal Synthesis of Spinel-Type Nonstoichiometric Cobalt Gallate Nanoparticles and Their Magnetic Properties

Xie

Numako

Naka

et al. 2023

Crystal Growth & Design

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Spinel-type metal oxide nanoparticles are known to exhibit various properties, which can be further enhanced by the synthesis of nonstoichiometric nanoparticles. In this work, we report the production of nonstoichiometric cobalt gallate nanoparticles (Co−Ga NPs) with larger inversion parameters that resulted in enhanced magnetic properties compared to previous studies. The synthesis of nonstoichiometric nanoparticles was realized by a supercritical hydrothermal process and without performing calcination at a high temperature which tended to synthesize thermodynamically stable stoichiometric products. We synthesized nonstoichiometric Co−Ga NPs with a controllable Co/Ga molar ratio, morphology, and particle size at different pH values of the precursor solutions. By applying X-ray absorption fine structure analysis at Ga K-edge, Co K-edge, and Rietveld refinement, nonstoichiometric Co−Ga NPs were found to have large numbers of cobalt atoms occupying octahedral sites compared to CoGa 2 O 4 . Their superparamagnetic behavior with enhanced spontaneous magnetization at room temperature owing to percolated superexchange interaction of J BB was observed for the first time. We also proposed a possible formation mechanism of nonstoichiometric Co−Ga NPs from cobalt gallium nitrate layered double hydroxides in the precursor solutions.

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Section: Introductionmentioning

confidence: 99%