Keywords octahedral site tetrahedral site zinc ferrite nickel ferrite inverse spinel. Electronic structure of normal and inverse spinel ferrites. It also describes the important magnetic properties of these spinel ferrites. Spinel, ferrite, mnfe2o4, cofe2o4, nife2o4, znfe2o4, nanoparticles, hydrothermal synthesis, neutron, x ray, powder diffraction, rietveld refinement. Spinel mgal2o4 c 20012005 mineral data publishing, version 1 crystal data. The xray diffraction pattern shows the braggs peak which belongs to cubic spinel structure. They obtained ferrites with a single spinel crystalline structure and the crystallite size was in a range within 5 and 8 nm, however the particle size was not evaluated. Crystal structure and magnetic interactions of ferrites. The most commonly used materials of nanoparticles in magnetic fluids are chemical stable spinel 23 ferrites. Introduction commercially speaking, spinel ferrites are important materials because of their good magneticelectrical properties 1,2. Generally, spinel ferrite is a cubic spinel structure, and belongs to the space group o h 7 fd3m. Electronic structures of normal and inverse spinel ferrites from first principles.
However, the degree of inversion in the nps is often close to 0. Synthesis and characterization of spinel oxide compounds. Types of ferrites type structure general formula examples spinel ferrites cubic a. The spinel ferrites have cubic structure belonging to space 20 30 40 50 60 70 80 200 400 600 800 1200 1400 2 theta degree nife 2. More commonly used is the wet chemical coprecipitation production. A unit cell comprises eight tetrahedral and 16 octahedral sites, with formula a b 2 o 4, where a and b refer to the tetrahedral and the octahedral cation sites respectively, in a fcc anion oxygen sub lattice. Synthesis and characterization of spinel oxide compounds ab 2 o 4doctoral thesissummary. Pdf electronic structures of normal and inverse spinel. The feasibility of incorporating cd and ni in hematite was studied by investigating the interaction mechanism for the formation of cd x ni 1x fe 2 o 4 solid solutions cnfs from cdo, nio, and. 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. We apply the selfinteraction corrected local spin density approximation to study the electronic structure and magnetic properties of the spinel ferrites mnfe2o4, fe3o4, cofe2o4, and nife2o4. Superparamagnetism is a unique feature of magnetic nanoparticles and is crucially related to. Characterization of magnesium substituted nickel ferrites.
There is a large group of ferrites possessing such a structure. Crystalization in spinel ferrite nanoparticles 353 fig. Depending upon the nature magnetic or nonmagnetic and distribution. Magnetic spinel ferrite mfe 2 o 4 m mn, co, ni, zn nanoparticles have been prepared via simple, green and scalable hydrothermal synthesis pathways utilizing sub and supercritical conditions to attain specific product characteristics. Analogous notations are adopted for other structures. Sadhana3 1materials research center, indian institute of science, bangalore560012, india. Hard ferrites with the magnetoplumbite hexagonal structure such as ba and sr hexaferrites. Mesoporous nickel ferrites with spinel structure prepared. Adrian iulian borhan synthesis and characterization of spinel oxide compounds ab2o4 1.
Characterization of magnesium substituted nickel ferrites nanoparticles synthesized using combustion technique. An overview of the structure and magnetism of spinel. Soft ferrites introduction the nature of soft ferrites composition ferrites are dark grey or black ceramic materials. M2 is tetrahedral, m3 is octahedral example mg2t2al3oo24 in verse spinal. Magnetic and electrical properties of mnxcu1xfe2o4 ferrite 1.
The hexagonal ferrite lattice is similar to the spinel structure, with the. Ferrites, spinel structure, magnetic properties, mncu ferrites. Totally in an unit cell, there will be 8 tetrahedral 8 a sites and 16 octahedral 16b sites. 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. Spinel ferrites, with common formula of mfe 2 o 4 m.
Chapter 1 introduction, types and applications of ferrites. Commonly as octahedra, to 30 cm, may show dodecahedron or cube faces, rarely as dodecahedra. Spinel ferrites structures partially determine by oxygen ion in a cubic arrangement there are two types of interstitial spaces between the anion tetrahedral coordinate site and octahedral coordinate site. Copper ferrite, belonging to the wide and technologically relevant class of spinel ferrites, was grown in the form of tcufe2o4 nanocrystals within a porous matrix of silica in the form of either an aerogel or a xerogel, and compared to a bulk sample.
If you have a disability and are having trouble accessing information on this website or need materials in an alternate format, contact web. Structural phase stability and magnetism in co feo spinel. These are the spinel structure, on which ferrites and other magnetic oxides are based, the perovskite structure, which is adopted by ferroelectric and superconducting oxides, and the rutile structure, which is a common binary 6. Electronic structure of normal and inverse spinel ferrites from first. A singlephase nicuzn ferrite with cubic spinel structure without any. Structural, electrical, and dielectric properties of. The focus then shifts to the use of microemulsions as nanoreactors for the synthesis of spinel ferrites.
The structure is related to the spinel structure in which the oxygen lattice, f. The preparation of ferrite nanoparticles for magnetic fluids synthesis needs a special technology. Magnetic nanoparticles of spinel ferrites are of great interest in fundamental science, especially for addressing the fundamental relationships between magnetic properties and their crystal chemistry and structure. Soft ferrites with the cubic spinel structure such as nizn, mnzn, and mgmnzn ferrites. From raman spectra, the raman shift of pure nife 2 o. Structural, magnetic, and optical properties of zinc and copper substituted nickel ferrite nanocrystals. This is a pdf file of an unedited manuscript that has been accepted for. Synthesis, structure and magnetic properties of spinel. Like most of the other ceramics, ferrites are hard, brittle, and poor conductors of electricity. The xray diffraction technique was employed to confirm the single phase formation of nickel ferrite. The directcurrent dc electrical resistivity was found to be highest for pure ambfo and then started to decrease with increase in the lizn ferrite lzf content in. Spinel, perovskite, and rutile structures chemistry. Pdf we apply the selfinteraction corrected local spin density %siclsd approximation to study the electronic structure and magnetic. The spinel structure of ferrites as possessed by mineral spinel mgal2o4 was first determined by bragg and nishikawa in 1915.
Crystalization in spinel ferrite nanoparticles intechopen. Ferrites are usually ferrimagnetic ceramic compounds derived from iron oxides. Normal spinel structures are usually cubic closepacked oxides with eight tetrahedral and four octahedral sites per formula unit. Ferromagnetic properties of zn substituted spinel ferrites. Synthesis of magnetic spinel ferrite cofe2o4 nanoparticles. Spinel is mgal2o4 many compounds adopt this type of structure. Incorporation of cadmium and nickel into ferrite spinel. The spinel crystal structure is determined primarily by the oxygen ions lattice. 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. Mnfe2o4 ferrites have a nanocrystalline structure with a crystallite size of about 30 and 40 nm for cases 1. Ferrites are widely used in transformer and inductors for telecommunications, power conversion and interference suppression. Spinel ferrites are represented by the formula unit ab2o4.
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. In bulk, the normal or inverse spinel structure usually dominates. Structural, magnetic, and optical properties of zinc and. In order to further reveal the structural properties of the ni, cu, cofe 2 o 4, raman spectra of the ferrites calcined at different temperatures were recorded, as depicted in fig. The metaltosemiconductor transition temperature decreased from 340 k to 330 k with increase in the lzf content, being mainly due to spin canting and phase structure conversion. C for 1 hr to obtain good crystalline phase and was used for further study. Onerlr nno alexenone nevnorsky department of chemistry arizona state university tempe, arizona 85287 abstract electrostatic lattice energy calculations and consideration of the structure of the spinel. Ferromagnetic properties of zn substituted spinel ferrites for high frequency applications k. Cbse 12 chemistry the solid state unit cells number of atoms in a unit cell duration. The radii of the oxygen ions are several times larger than the radii of the metallic ions in the compound. Magnetic properties of soft ferrites research papers. The structure of the spherical mesoporous nickel ferrites was studied by transmission electron microscopy, powder xray diffraction, and n2 adsorptiondesorption isotherm measurements. Crystallographic and magnetic properties of the spinel. Crystalline and magnetic structureproperty relationship.
Pdf electronic structures of normal and inverse spinel ferrites. Pdf recent developments show that the exceptional physical, optical, magnetic, and electrical properties of spinel ferrite sf nanomaterials. Ferrites are hard, brittle, ironcontaining, and generally gray or black and are polycrystallinei. Xray diffraction results showed that the cnfs crystallized into spinel structures with increasing lattice parameters as the cd content in the precursors was increased. The general chemical formula for the spinel type ferrites is ab2o4, where a and b represent divalent and trivalent metal ions cations, respectively and o represents the oxygen ions. The spinel structure consists of a facecentered cubic lattice of oxygen ions with two types of.
Magnesium ferrite, mgfe o is structural properties of ferrites by means of the 24 regarded as an important candidate of the spinel family. View magnetic properties of soft ferrites research papers on academia. The crystal, magnetic and micro structures of the prepared crystallites have been elucidated through meticulous characterization employing several. Crystalline and magnetic structureproperty relationship in spinel. Due to the large electronegativity oxygen the ionic type of bonds prevails in almost all oxide spinels. Ferrites have a cubic spinel structure with eight formula units per unit cell. Structural and magnetic properties of nanosized nicuzn. This type spinel ferrite are schematically illustrated in figure3. Ferrites are ceramic magnetic materials capable of com bining the resistivity of an insulator with relatively high. Review of the relevant literature the spinel structure. The general composition of such ferrites is mefe2o4 where me represents one or several of the divalent. A unit cell comprises eight tetrahedral and 16 octahedral sites, with formula a b 2o 4, where a and b refer to the tetrahedral and the octahedral cation sites respectively, in a fcc. Most modern magnetically soft ferrites have a cubic spinel structure. Ferrite, a ceramiclike material with magnetic properties that are useful in many types of electronic devices.
Structural and magnetic properties of nanosized nicuzn ferrites. The material crystallized in cubic spinel structure with lattice parameter of about 8. Mesoporous nife2o4 spheres of high specific surface area 278 m2 g1 with a highly crystalline framework were prepared by adjusting the amount of structure. Magnetite fe 3o 4, ferrites nife 2o 4 and cofe 2o 4 have inversed spinel structure. One of the main advantages of ferrites is the possibility for tuning the magnetic properties by varying simply either the divalent cation or the arrangement of the metals into the spinel structure. 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.
1452 549 453 1602 1479 1072 134 1282 188 1529 996 1526 1424 653 230 1492 1083 1165 819 587 152 253 1162 1532 1126 438 1336 523 147 1459 176 911 1453 1332 33 662 288 85 1288 786 1204 1398 217 1218 764 896 1346