Mg0.50Cu0.5-xNixFe2O4 Spinel Nanoferrites: Structural, Electrical, Magnetic and Y-K Angle Studies (original) (raw)
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Mg0.50Cu0.5-xNixFe2O4 Spinel Nanoferrites: Structural, Electrical, Magnetic and Y-K Angle Studies
Spinel Nanoferrites of composition Mg 0.50 Cu 0.5-x Ni x Fe 2 O 4 (0.00≤x≤0.50) were synthesized by chemical co-precipitation method. The structural, morphological and magnetically changes due to varying concentrations of metal ions of Cu and Ni in the prepared nanoferrites were studied. XRD confirmed the formation of single phase spinel ferrite with crystalline sizes in between 16-29 nm, and the lattice parameter (a) found to decreases with increase of Ni concentration. Electrical resistivity of the prepared nanoferrites with varying nickel and copper concentrations x observed to follow Arrhenius relation and also exhibited the semiconductor behavior. The magnetic hysteresis curves clearly indicate the soft nature of the prepared samples. Saturation magnetization (M s ) increases with Ni content. This effect is related to the magnetic moments of Ni +2 ions. The Y-K angles increase with increasing Ni content, and suggest a non-collinearity Néel type of ordering of the Y-K type. The increase in the Y-K angles also suggests the increase in triangular spin arrangements on B sites, which subsequently lead to increment in A-B interactions.
Crystalization in Spinel Ferrite Nanoparticles
InTech eBooks, 2012
ferrites and to prepare magnetic carriers based on them. Ferrites have three different structural symmetries: garnet, hexagonal and cubic which are determined by the size and charge of the metal ions that balance the charge of the oxygen ions, and their relative amounts [5]. In this review, the focus will be on spinel ferrites nanocrystals because, they are regarded as two of the most important inorganic nanomaterials because of their electronic, optical, electrical, magnetic, and catalytic properties.Moreover, the majority of the important ferrite are spinel ferrite [6]. 2.1 Garnets ferrites The general formula for garnets is Me 3 Fe 5 O 12 , where Me is one of the rare earth metal ions, including Y, La and Gd. The cubic unit cell contains 8 formula units or 160 atoms, which can be described as a spatial arrangement of 96 O 2-with interstitial cations. Yttrium iron garnet Y 3 Fe 5 O 12 (YIG) is a well-known garnet. The coordination of the cations is considerably more complex than spinels, with 24 Y 3+ in dodecahedral sites, 24 Fe 3+ ions in tetrahedral sites and 16 remaining Fe 3+ in octahedral sites. Similar to spinels and hexagonal ferrites, a wide range of transition metal cations can substitute Y 3+ or Fe 3+ ; especially rare earth ions may replace the ions on octahedral and dodecahedral sites. Each type of lattice site will accept other metal ions at dodecahedral sites, octahedral sites and at tetrahedral sites. Thus pentavalent ions such as V 5+ and As 5+ can occupy tetrahedral sites, while Ca2+ substitute ions on dodecahedral sites [7]. 2.2 Hexagonal ferrites Hexagonal ferrites are widely used as permanent magnets and are characterized by possesing a high coercivity [4].Their general formula is MeO•6Fe 2 O 3 where Me can be Ba, Sr, or Pb. The hexagonal ferrite lattice is similar to the spinel structure, with the oxygen ions closely packed, but some layers include metal ions, which have practically the same ionic radii as the oxygen ions. This lattice has three different sites occupied by metals: tetrahedral, octahedral, and trigonal bi pyramid (surrounded by five oxygen ions).
Journal of Magnetics, 2011
Magnetic properties of highly zinc-substituted manganese ferrites are discussed on the basis of cation distribution. High throughput neutron powder diffractometry indicates that the prepared samples possess a nearly normal spinel structure, where the substitution of nonmagnetic zinc ions mainly causes the dilution of magnetic ions in the A-sublattice and consequently affects bond-randomness in the B-sublattice. On the other hand, the estimated occupancy of manganese ions in the B site indicates that random anisotropy effects due to local Jahn-Teller distortions gradually weaken with the substitution. Bulk magnetometry indicates that the substitution smears the transition from a paramagnetic phase to a soft-magnetic phase. Furthermore, at lower temperatures, such a soft-magnetic phase is destabilized and a magnetic glassy state appears. These features of the magnetic properties of dilute spinel ferrites are discussed from the viewpoint of the above-mentioned various types of disorders.
Electronic structures of normal and inverse spinel ferrites from first principles
Physical Review B, 2006
We apply the self-interaction corrected local spin density approximation to study the electronic structure and magnetic properties of the spinel ferrites MnFe2O4, Fe3O4, CoFe2O4, and NiFe2O4. We concentrate on establishing the nominal valence of the transition metal elements and the ground state structure, based on the study of various valence scenarios for both the inverse and normal spinel structures for all the systems. For both structures we find all the studied compounds to be insulating, but with smaller gaps in the normal spinel scenario. On the contrary, the calculated spin magnetic moments and the exchange splitting of the conduction bands are seen to increase dramatically when moving from the inverse spinel structure to the normal spinel kind. We find substantial orbital moments for NiFe2O4 and CoFe2O4.
Bulk Magnetic Properties of Nanosized Spinel Ferrites
International Journal of Research in Engineering and Technology, 2016
Nanosized Co0.5Zn0.5Fe2O4 and Cu0.5Zn0.5Fe2O4 were prepared using Co-precipitation method. Using a combination of x ray diffraction, Mössbauer studies and DC magnetization, the magnetic properties of nano sized Co0.5Zn0.5Fe2O4 and Cu0.5Zn0.5Fe2O4 have been studied. Although the preparation conditions were kept same, the particle size of Cu0.5Zn0.5Fe2O4 (2.4nm) were smaller than that of Co0.5Zn0.5Fe2O4 (5.8nm) as the formation of Cu0.5Zn0.5Fe2O4 is more exothermic in nature that the formation of Co0.5Zn0.5Fe2O4. The dependence of DC magnetization on particle size and cation distribution have been studied.
Impact of chemical composition on preparation of nanodimensional spinel ferrites
2015
The nanostructured manganese and zinc ferrite-type materials were synthesized using preparation methods such as co-precipitation or co-precipitation and mechanochemical treatment. The physicochemical techniques – Powder X-ray diffraction analysis (PXRD), Mossbauer and Fourier transform infrared (FTIR) spectroscopy were performed in order to establish the phase composition, structure and magnetic behavior of prepared nanodimensional ferrite-type samples. The PXRD results determined that single non-stoichiometric ferrite phase (ZnxFe3–xO4, x=0.25) as well as ferrite (ZnxFe3–xO4, x=0.5;1, MnxFe3–xO4, x=0.25;0.5;1) and additional akaganeite phases were obtained by co-precipitation procedure. The presence of ferrite and iron phases and elimination of akaganeite was achieved using high-energy ball milling. The synthesized nanosized manganese and zinc ferrite-type materials possess the mean crystallite size about 7–13 nm and 6–13 nm respectively. The superparamagnetic (SPM) and collective ...
In the present work, ferromagnetic Ni is slightly substituted for diamagnetic Mg spinal ferrites. The effect of Ni doping on the structural and magnetic properties of ferrites material in the form of NixMg1-xFe2O4 (x = 0.1,0.15,0.2,0.25, .0.3,0.35) has been the study. The Sol-gel auto Combustion method used to combine these substances uses urea as fuel. Sintered samples were shown using X-ray diffraction, Fourier Transform Infrared spectroscopy (FTIR) and a vibrating magnetometer sample. X-ray diffraction revealed that all the composite samples were pure cubic spinel arrays with a Fd3m space band and a permanent lattice that varied with Ni concentrations. the distribution of Ni 2 + ions and Mg 2+ ions in spinel ferrites indicates various changes in parameters such as tetrahedral ionic radius (rA), octahedral ionic radius (rB), hopping length (LA and LB). Fourier Transform Infrared (FT-IR) simulations showed wire vibration at the tetrahedral site and Octahedral site. spinel ferrites M-H curves are recorded at room temperature indicating normal hysteresis loop indicating the magnetic field.
Spinel ferrite nanoparticles are potential candidates for multiple biomedical applications. Spinel ferrite nanoparticles have been studied extensively for understanding physical, chemical, electro-optical as well as magnetic properties which are fascinating due to cationic distributions corresponding to tetrahedral sites and octahedral sites in a cubic phase. Biocompatibility and large magnetic moment are basic requirements in spinel ferrite nanoparticles for efficient functioning in specific application purpose. Fe3O4 (magnetite) is an important member of spinel ferrite group with high chemical stability and ferrimagetic material property at nanodimension. Superparamagnetic state and biocompatibility of magnetite (Fe3O4) spinel ferrite nanoparticle has already been proven. Spinel ferrite magnetite nanoparticles have been developed based on precipitation of iron oxide using ferric and ferrous ions at the ratio 2:1 in alkaline media at and above 1000C. The experimental parameters hav...