Nanocrystalline spinel ferrites by solid state reaction route 509 table 1. Structural properties and electrical conductivity of. Nanostructured nife2o4, mnfe2o4 and niznfe2o4 were synthesized by aliovalent ion doping using conventional solidstate reaction route. The positive ferrite znfe2o4 usually exhibits antiferromagnetism. Due to similar unit cell parameters, the xray diffraction pattern of fe 3o 4 hardly differs from that of other spinel ferrites, especially when the re. Particle diameter, saturation magnetization and coercive field for the nife2o4 samples. Photoelectrochemical and theoretical investigations of spinel type ferrites m xfe 3 xo 4 for water splitting. A series of gdsubstituted cobalt based ferrites of nominal composition cogd2xfe22xo4 for x 0. Aluminum doped manganese ferrites with have been prepared by the double ceramic route. Crystalline and magnetic structureproperty relationship in spinel. Typical example of mixed spinel ferrites are mgfe 2o4 and mnfe 2o4. The spinel structure of ferrites is shown indicating th.
Spineltype nanosized mixed ferrite containing mg and zn. Ferrites are usually ferrimagnetic ceramic compounds derived from iron oxides. The spinel ferrites crystallize in the face centered cubic fcc spinel structure, space group fd 3 with combining macron m, illustrated in fig. Experimental the experiments were performed in a radiofrequency rf thermal plasma reactor operating with a tekna. The spinel structure is named after the mineral spinel mgal x4, where x represents oxygen or one chalcogenic bivalent anion s te 2 and m a nd m are metallic ions. Chemical and structural properties of spinel ferrite nanocrystals are affected by their compositions and synthesis methods, and corresponding electric and magnetic properties. Dec 21, 2017 nickel laterite ore and zincbearing dust are multimetalassociated and intractable resources. The synthesis and magnetic structure characterization of spinel metastable nanoferrites have been investigated with much interest, and a lot of attention has been focused on the preparation and characterization of superparamagnetic metal oxide nanoparticles of spinel ferrites, mefe 2 o 4 metal me co, mg, mn, zn, etc. Nickelzinc ferrites are considered as one of the most versatile soft ferrites because of its high resistance and low eddy current losses 1. The surface morphology of the ferrite powders can be examined from sem micrographs fig. The valences have to fulfill the electroneutrality requirements.
A detailed investigation of the structural, electrical, magnetic and optical properties was carried out for the synthesized samples using xray diffraction xrd, currentvoltage iv measurements, vibrating sample magnetometer vsm and raman spectroscopy, respectively. Simple synthesis and characterization of cobalt ferrite. Hyper ne interactions in ferrites with spinel structure. The spinel ferrites have been applied for congored cr dye adsorption using. Numerous binary tm ferrites have been investigated for supercapacitor applications such as znfe 2o 4, 17,30 cofe 2o 4, 14 mnfe 2o 4, 37. The cation distributions were estimated from xray diffraction intensities of various.
There is a small amount of h 2 produced due to direct water splitting at this temperature ferrites introduction the nature of soft ferrites composition ferrites are dark grey or black ceramic materials. For some spinel transitionmetal oxides like ferrites, the coexistence of magnetism and ion storage ability make it possible to fabricate modulable devices controlled by liions 20,21,22,23. Structural phase stability and magnetism in co feo spinel. Synthesis and characterization of nanostructured spinel. Structural, magnetic, and catalytic evaluation of spinel. Spinel ferrites have been studied extensively due to easy to synthesis and abundant uses in technological and industrial applications. This family is classified into the fd3m space group with the general formula m 1.
Various substituents of magnetic and nonmagnetic nature like ni, zn, al, etc. Magnetite fe3 o4, also called loadstone, is a genuine ferrite and was the first magnetic material known to the ancient people. Physical revie% b vo lume 19, number 1 1 january 1979 exchange constants in spinel ferrites c. Facile synthesis of spinel ferrites with enhanced magnetic. These species, spinel m 2 o 3 and meo respectively, are then exposed to 10,000 moles h 2 o and the h 2 produced is shown in fig. Structural and magnetic properties of spinel ferrite nanoparticles. Photoelectrochemical and theoretical investigations of spinel.
Photoelectrochemical and theoretical investigations of. All of the main peaks are indexed as the spinel mgfe 2 o 4 in the standard data shimadzu 6000 xray diffractometer equipped with cuk radiation of. Soft ferrites introduction the nature of soft ferrites composition ferrites are dark grey or black ceramic materials. The materials are characterized by xray diffraction xrd, fourier transform infrared spectroscopy ftir, and transmission electron microscopy tem. Preparation and characterization of manganese ferrite. Spinel ferrites are represented by the formula unit ab2o4. Cobalt ferrites are deposited on al 2 o 3 substrates via atomic layer deposition, and the efficacy of using these in a ferrite water splitting redox cycle to produce h 2 is studied. Many ferrites adopt the spinel structure with the formula ab 2 o 4, where a and b represent various metal cations, usually including iron fe.
From xray diffraction patterns, all samples showed single cubic spinel structure. Nanocrystalline spinel ferrites by solid state reaction route t k kundu and s mishra department of physics, visvabharati, santiniketan 731 235, india abstract. Spinel profile since first opening our doors over 4 decades ago, spinel has been focused upon the research, development, production and sales of ferrites and accessories for electronic products. Spinel ferrites are mixed valence oxides where oxygen anions form a close. Comprehensive and cooperative utilization of zincbearing dust and nickel laterite ore for the preparation of spinel ferrites with enhanced magnetic properties by a facile process was proposed. Pdf electronic structures of normal and inverse spinel. The rich crystal chemistry in spinel ferrite systems offers excellent opportunities for understanding and finetuning the superparamagnetic properties of nanoparticles by chemical manipulations. Since in an inverse spinel there are two types of ions on the b sites, one divalent and the other trivalent, nttel for simplicity assumed. Mixed nizn ferrite has been commercially used in radio frequency circuits, high quality filters, rod antennas and transformer cores 2,3. If there is unequal number of each kind of cations on octahedral sites, the spinel is called mixed. Synthesis and structural properties of mgfe2o4 ferrite. The general composition of such ferrites is mefe2o4 where me represents one or several of the divalent.
Reversible control of the magnetization of spinel ferrites. It has been proposed that the 2line type consists of extremely. The unit cell of spinel ferrites is composed of 32 oxygen atoms in cubic closed packed arrangement distributed in tetrahedral a. Crystalization in spinel ferrite nanoparticles intechopen. Synthesis of magnetic spinel ferrite cofe2o4 nanoparticles. Spinel ferrites possess the crystal structure of the natural spinel. Structural properties and electrical conductivity of copper. Structural, magnetic, and optical properties of zinc and. Pdf a valuable sitedirected application in the field of nanomedicine is targeted drug delivery using magnetic metal oxide nanoparticles by. This chapter focuses on the relationship between structural and magnetic properties of cubic spinel ferrite mfe2o4 m mg, mn, fe, co, ni, cu and zn nanoparticles nps. These results encourage further development of mwcnts. The useful properties of the spinel ferrites mostly depend upon the chemical composition, preparation methods, sintering temperature, nature of the. The space group for a spinel group mineral may be fd 3 m the same as for diamond, but in some cases such as spinel itself, mgal 2 o 4 it is actually the tetrahedral f 4 3m normal spinel structures are usually cubic closepacked oxides with eight tetrahedral and four octahedral sites per formula unit. The crystal structure of spinel ferrite has two interstitial sites namely tetrahedral a and octahedral.
Structural and magnetotransport properties of thin films. This structural compatibility allows one to combine thin layers of very different materials to design multifunctional epitaxial heterostructures. The crystal structure of spinel ferrite is based on cubic close packed oxygen and ions. Most of the spinel ferrites form cubic spinel structure with oxygen anions in fcc positions and cations in the tetrahedral and octahedral coordinated interstitial lattice sites, forming the a and b sublattices 1. While high quality single crystals are challenging to grow, thin. At the same time, since the nanoparticle np surface is reactive toward many chemical groups, it provides great versatility for further functionalization of the nanosystems. It comes from the possibility of tuning their magnetic properties by careful manipulation of the synthetic conditions. The spinel structure of ferrites as possessed by mineral spinel mgal2o4 was first determined by bragg and nishikawa in 1915. The parent compound of the spinel ferrites, fe 3 o 4, has been widely studied in the bulk due to its socalled verwey transition, which is a structural and charge and orbital ordering phase. Different spinel ferrites such as nife2o4, cdfe2o4, znfe2o4 and cufe2o4 have been studied for various gassensing applications 2,6,12,14. One can remark the high tendency of the fine crystallites to. After the physical blending of the elastomer with the magnetic fillers, the resulting blend must be cured for making rubber ferrite composites. The xrd patterns of the calcined mgfe 2 o 4 are shown in fig1.
Chemical tuning of the optical band gap in spinel ferrites. Epitaxial growth of highlycrystalline spinel ferrite thin. Then, key parameters of magnetic nps representing their structural and magnetic properties are summarized with link to the relevant. Review of the relevant literature the spinel structure. Ni zn ferrite is mixed spinel in which the tetrahedral a. Sadhana3 1materials research center, indian institute of science, bangalore560012, india. The spinel ferrites comprise an important class of candidate materials that could serve as the magneticallyactive layer in room temperature, alloxide devices.
Normal spinel structures are usually cubic closepacked oxides with eight tetrahedral and four octahedral sites per formula unit. The synthesized nife 2o 4 and mnfe 2o 4 ferrites have a nanocrystalline structure with a crystallite size of about 30 and 40 nm for cases 1 and 2. Pdf characterization of cobalt based spinel ferrites. Abstract crystalline magnesium ferrite mgfe2o4 spinel oxide powder was synthesized by. The substitution of copper in ni ckel ferrite modifies the properties of nickel ferrite which are useful in many device applications. Nanostructured spinel ferrites have gained a great deal of attention. Structural, magnetic and electrical properties of the lithium. Ferromagnetic properties of zn substituted spinel ferrites for high frequency applications k. A spinel ferritehercynite watersplitting redox cycle. Synthesis of spinel ferrites in radiofrequency thermal plasma. An overview of the structure and magnetism of spinel ferrite. Although the magnetic properties of spinel cobalt and nickel ferrites have been studied by several research groups,3,8,24,21,38,39 there exist very few reports in the literature on the magnetic properties of co 0. The patterns were compared with standard data jcpds pdf card no. Synthesis, structural and magnetic properties of copper.
Epitaxial growth of highlycrystalline spinel ferrite thin films on perovskite substrates for alloxide devices. Due to enhanced kinetic energy of ablated species at low. In the present study, effect of nickel substitution to copperzinc ferrite on structural, microstructural and infrared properties of nanocrystalline. The spinel ferrites have been applied for congored cr dye adsorption using batch technique. The unit cell of spinel ferrites is composed of 32 oxygen atoms in cubic closed packed. A novel synthesis yielding macroporous cafe2o4 sponges. Nanosized spinel ferrites mfe 2 o 4 m ni, co, and zn have been prepared by solgel autocombustion method using citric acid as a fuel agent. Nanostructured spinel manganese cobalt ferrite for high. Electrical properties of spinel ferrites hopping at octahedral bsites. The space group for a spinel group mineral may be fd 3 m the same as for diamond, but in some cases such as spinel itself, mgal.
The spinel structure of ferrites is shown indicating th openi. Ac cording to crystal structure, nickel ferrite is an inverse spinel ferrite and possesses high electrical resistivity and low eddy current losses. Many ferrites adopt the spinel structure with the formula ab 2 o 4, where a and b represent various metal cations, usually. The physical properties of ferrites are very sensitive to microstructure, which in turn critically depends on the manufacturing process. This type spinel ferrite are schematically illustrated in figure3. In some situations, the ferrite structure might have a structure that is in between the normal and inverse spinel structures.
The structure and magnetic properties of asprepared spinel ferrites were characterized by xray. B, condensed matter 7417 august 2006 with 2,364 reads. Recent spectroscopic work on nickel ferrite nife 2o 4 also revealed a hierarchy of band gaps,16,17 and a favorable overlap with the solar spectrum. Synthesis and characterization of nanostructured spinel ferrites.
Structural phase stability and magnetism in co feo spinel oxide. Manganese and zinc spinel ferrites blended with multi. In addition, among ferrospinels zinc ferrites are used in gas sensing 14, 15, catalytic application 16, photocatalyst 17, 18, and absorbent materials 19. Spinel structure the spinel crystal structure is the most well example of uncompensated antiferromagnetism. Ferromagnetic properties of zn substituted spinel ferrites. An overview of the structure and magnetism of spinel. Spinel ferrite nanoparticles have attracted much attention because of their electronic, magnetic. The major difference among these two ferrites is in their resistivity. The magnetic property of ferrite is the manifestation nature of ions and their.
Structural, magnetic and electrical properties of the. Worldwide research efforts are underway to find new applications for ferrites in addition to improving their existing functional properties. Magnetic properties of nizn ferrites by citrate gel method. Nickel laterite ore and zincbearing dust are multimetalassociated and intractable resources. Like most of the other ceramics, ferrites are hard, brittle, and poor conductors of electricity. Structural, vibrational, electrical, and magnetic properties. These materials, with composition tmfe 2 o 4 where tm is a transitionmetal cation, are ferrimagnets that can retain their magnetism to above 800k e.
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