scholarly journals Hydrothermally Synthesized Mg-Based Spinel Nanoferrites: Phase Formation and Study on Magnetic Features and Microwave Characteristics

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2274 ◽  
Author(s):  
Chien-Yie Tsay ◽  
Yi-Chun Chiu ◽  
Chien-Ming Lei
Keyword(s):  
Spinel Phase ◽  
Ferrite Nanoparticles ◽  
Microwave Properties ◽  
Spectroscopy Analysis ◽  
Hydrothermal Route ◽  
Paramagnetic Resonance ◽  
Nanocrystallite Size ◽  
Spinel Nanoferrites ◽  
Electron Paramagnetic ◽  
Microwave Characteristics

Three kinds of magnesium-based spinel nanoferrites with the chemical formulas of MgFe2O4 (Mg ferrite), Mg0.9Mn0.1Fe2O4 (Mg-Mn ferrite), and Mg0.9Mn0.1In0.1Fe1.9O4 (Mg-Mn-In ferrite) were synthesized by hydrothermal route. We report the composition-dependent magnetic parameters and microwave properties of Mg-based ferrite nanoparticles. XRD results revealed that the Mg-based ferrite nanoparticles exhibited a cubic spinel structure and had an average nanocrystallite size in the range of 5.8–2.6 nm. Raman spectroscopy analysis confirmed the formation of cubic-spinel phase Mg-based nanoferrites. The room-temperature magnetization measurements indicated that the Mg ferrite nanoparticles had superparamagnetic behavior; whereas the Mg-Mn and Mg-Mn-In ferrite nanoparticles exhibited a paramagnetic nature. The microwave properties of obtained ferrite nanoparticles were studied by alternating current (AC) magnetic susceptibility measurement and electron paramagnetic resonance (EPR) spectroscopy. It was found that the un-substituted Mg ferrite sample exhibited microwave characteristics better than those of the Mn substituted and Mn-In co-substituted Mg ferrite samples.

Fabrication of Mn2O3 Nanorods and their Different Paramagnetic Properties

2011 ◽  
Vol 233-235 ◽  
pp. 2252-2257 ◽  
Author(s):  
Yan Ge Zhang ◽  
Jing Chen ◽  
Bao Jun Huang ◽  
Da Peng Li
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Magnetic Properties ◽  
Thermal Treatment ◽  
Calcination Temperature ◽  
Hydrothermal Route ◽  
Paramagnetic Resonance ◽  
Calcination Temperatures ◽  
Mild Conditions ◽  
Electron Paramagnetic ◽  
Paramagnetic Properties

Mn2O3 Nanorods have been successfully synthesized under mild conditions by hydrothermal route following by thermal treatment at different calcination temperatures. Techniques of XRD, TEM, HRTEM, ED and XPS have been used to characterize the nanorods. The magnetic properties of the Mn2O3 nanorods synthesized at different calcination temperature have been studied using electron paramagnetic resonance (EPR) technique. And the evolved different EPR signals have also been discussed.

Electron paramagnetic resonance of ferrite nanoparticles

2001 ◽  
Vol 89 (4) ◽  
pp. 2293-2298 ◽  
Author(s):  
Yu. A. Koksharov ◽  
D. A. Pankratov ◽  
S. P. Gubin ◽  
I. D. Kosobudsky ◽  
M. Beltran ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Ferrite Nanoparticles ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

Evidence of a Cationic Substitution Domain in Lithium-Manganese Spinels

1998 ◽  
Vol 53 (9) ◽  
pp. 771-778 ◽  
Author(s):  
C. B. Azzoni ◽  
M. C. Mozzati ◽  
A. Paleari ◽  
V. Massarotti ◽  
M. Bini ◽  
...  
Keyword(s):  
Spinel Phase ◽  
Tetrahedral Site ◽  
Reactive System ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
Lithium Manganese ◽  
Cationic Substitution ◽  
Cation Sites ◽  
Electron Paramagnetic ◽  
Lithium Manganese Spinel

Abstract Magnetic susceptibility measurements and electron paramagnetic resonance spectra of samples prepared from the reactive system MnO/Li2CO3 with different starting Li cationic fraction x are analyzed, taking into account the structural and compositional information provided by x-ray diffraction. Parent phases, as Mn2O3 , Mn3O4 and Li2 MnO3 , arise together with the lithium-manganese spinel as a result of Li-deficiency or Li-excess with respect to the x = 0.33 composition pertinent to the stoichiometric LiMn2O4 spinel. The data show that the spinel phase can sustain a partial Li-Mn substitution in the cation sites, according to compositional models described, for x > 0.33, by Li1+y Mn3+1-3y Mn4+1+2y O4 (Li-rich spinel) and, for x< 0.33, by Li1-|y| Mn2+|y| Mn3+1+|y| Mn4+1-|y| O4 (Li-poor spinel). Paramagnetic resonance data of the Li-poor spinel phase are analyzed to discuss the possible oxidation state of Mn in the tetrahedral site.

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