Analysis of Ferrous Ferrite (Fe3O4)

Analysis of Ferrous Ferrite (Fe3O4)1.1 INTRODUCTIONThe naturally occurring ferrite is the ferrous ferrite (Fe3O4) as adulterate stone. In early days it was called as ferrocharismatic material. L.Neel, tells us that these materials ar ferro charismatic material kayoed-of-pocket to uncompensated anti twin spin arrangement. Due to interesting intrinsic properties magnetic materials be separate into Ferromagnetic materials, Ferrites. In last decades , in the field of the ferrites expensive instruction was done by many contributors and found to be technically, commercially utilizable magnetic material. These materials be at heights frequencies, high electrical resistance of magnetic temperature coefficient of resistance along with low magnetic loss.Basically, Ferrous ferrite (Fe3O4) contain double oxides FeO and Fe2O3 . The properties of these materials are alter by substituting double fight ion by divalent cation like Cd2+,Mg2+,Ni2+,Zn2+,Cu2+,Co2+ etc. from transition el ement. The spinel ferrites are be as MFe2O4, where M is divalent cations. The magnetic properties are significantly change by substituting trivalent iron ion by Al3+,Cr3+,Mn4+, Ti4+,Sn4+, Gd3+,Nd3+ etc. for grumpy applications because of their interesting magnetic and electrical properties with chemical and thermal stabilitiesGadkari A.B et.al. (2010).The applications of these materials in field like electrical components, memory devices, microwave devices telecommunications, electronic industries, dada storage, entropy going due to its high resistivity and low power losses. Ernst Schloeman et al. (2000)Ferrites are of ii types,one is hard ferrite and other(a) is soft ferrite. The material which are easily magnetized and demagnetized, it is called soft magnetic material .That means, it can interpose or transfer magnetic energy in jump or other changing wave forms. The ferromagnetic materials like iron, plate, cobalt and close to of the rare earths materials shows a unique magnetic behavior. All the magnetic moments of the unmarried ions or atoms are aligned correspond to some particular oversight and the unpaired electron spins line up parallel with each other in the ferromagnetic material. The region in which magnetic dipoles align parallel to each other is called a domain. The geomorphologic properties of ferrite are very important. The structural properties of ferrites mainly depends on the manufacturing process of ferriteMangalaraja R.V. et al. (2003).In of import science, magnetic spinel ferrites are of great importance. They are useful especially for find out the fundamental relationship between magnetic properties and their crystallisationchemistry and social system Kalonji G.et.al.(1999). They find extensive applications in microwave devices, radar, digital recording, ferrofluids, catalysis and magnetic refrigeration systems Horvath M.P. et.al. (2007). For the spinel ferrite the general grammatical construction is AB2O4and it is con sisting of an al just about perfect cubic closed packed oxygen arrangement, with the cations residing on tetrahedral and octahedralinterstices. directlyadays, magnetic materials are used in various fields. The soft magnetic materials can be attracted to a permanent magnet and the hard magnetic materials become a permanent magnet. In case of soft magnetic materials, the coarse magnetic fields cannot be generated to the outside but in hard magnetic materials it generates magnetic fields. The magnetic materials like iron, cobalt and nickel ordinarily reveal prominent magnetic proportion. In industry, the ferromagnetic materials are widely used. In case of surface and alloy magnetic materials, due to their lower electrical resistivity the initial permeability and magnetic liquidise density is high and loss in eddy current is large at high frequencies. Nowadays, high-frequency characteristics are more useful, so this is occurred in ferrites which is multiplying the supple films. Due to higher electrical resistivity, the soft ferrites has ex cellphoneent characteristics at high frequency. They are abundantly used for inductors or core materials of transformer. The hard ferrite is overly used abundantly as permanent magnets for speakers and motors.The soft ferrite is used into an alternating magnetic field. Ferrites are chemical abstruses. They are composed of a ceramic material along with iron oxide as their main component. The magnetic property of the ferrite is due the structure and the arrangement of the ions in the sub lattice.1.2 SPINEL COMPOUNDSThe word spinel which is derived from Italian spinella, diminutive of spine, thorn (from its sharply pointed crystals). In the cubic system, Spinel crystallizes forming octahedral crystals. In spinel extremely group there are at least 30 oxide minerals included. The volume of spinel compounds belongs to the space group Fd3m. The formula for the principal member of the group has, AB2O4 out of which A is a divale nt metal ion such as magnesium, iron, nickel, atomic number 25 and zinc. The B is trivalent metal ions such as aluminium, iron, chromium and/or manganese. Also, titanium Ti4+ and Pb2+ etc. may occupy this internet site. The solid solutioning which is common process in this group of minerals that means they may contain certain percentages of opposite ions in any particular specimen Adams, D. M (1974). The oxygen ions are mostly larger than the metallic ions and the spinel structure can be organize by a cubic close packing of O2- ions, in most oxide structures in which the cations (e.g. Co2+, Fe3+) occupy certain interstices. So, the structure of a spinel compound and the highly symmetric structure of diamond is same. The position of the A ions and the positions of degree centigrade atoms occupied in the diamond structure is identical. In this group this could treat the relatively high hardness and high density. The arrangement in the structure of the other ions shows the symmetr y just like diamond structure. This arrangement of the ions verifies the octahedral crystal structure which is the predominant crystal form and excessively the trademark of the spinels. Now a day, there are well over a one hundred compounds are reported of the spinel structure. Most of them are oxides, sulphides, selenides and tellurides and some are halides. on that point are different cations may be introduced into the spinel structure and several saddle combinations are possible, therefore, almost any combination that added and balances eight positive charges of anionic charges Smyth,D.M.(2000),for example Co2+Fe23+O4, Mg22+Ti4+O4, Li1+Al3+Ti4+O4, Li0.51+Al2.53+O4 and Na21+W6+O4, etc.In oxide spinels, there are two types of cations which do not differ in size greatly because the spinel structure is stable only when the cations are rather medium sized and also the radii of the different ionic species in the same compound must be nearly equal. Therefore, similar cation combina tions occur in sulphides, e.g. Zn2+Al23+S4 and Cu22+Sn4+S4. Hence, in halide spinels e.g. Li21+Ni3+F4 and Li1+Mn23+/ 4+F4 in which cations are limited to charges of plus 1 and plus 2, give an boilersuit cation anion ratio of 3 as 4.Most spinels split up into three serial publication determined by a B metal represent aluminate serial with Al3+ (Hercynite, Gahnite, Galaxite) a magnetite series with Fe3+ (Magnetite,Magnesioferrite, Franklinite) the chromite series with Cr3+ (Chromite, Magnesiochromite). There is extensive cationic exchange (solid solution) within each series but very footling between the series King, R. J (2004).These spinels are classified on the root of the scattering of cations in the two principal sites which are tetrahedral site (T-) and octahedral site (O-) West, A. R. (1989), into three types.1.2.1 NORMAL SPINELIn normal spinel A (BB) O4, all the divalent (A) cations placed on the tetrahedral (T-) sites and the trivalent (B) cations present on the octahed ral (O-) sites. Which can be shown by the formula Atet B2oct O4. The examples of normal spinel areMgO.Al2O3 = MgAl2O4 (normal, parent mineral)ZnO.Fe2O3 = ZnFe2O4 (normal)FeO.Al2O3 = FeAl2O4 (normal)CoO.Al2O3 = CoAl2O4 (normal)MnO.Al2O3 = MnAl2O4 (normal)NiO.Al2O3 = NiAl2O4 - (normal)1.2.2 INVERSE SPINELThe opposite spinel, B (AB) O4, the divalent cations occupying on the O-sites and the trivalent cations which are equally divided among the T- and remaining other on O-sites. Which can be represented by formula, Btet A, Boct O4. The CoFe2O4 is conformably an inverse spinel with a formulaCoxFe1-x (Co1-xFe1+x) O4(with x 0)where x represents the cation distribution factor which discuss the fraction of tetrahedral sites occupied by Co2+ cations Guire, M. R.D (1989).CoO.Fe2O3 = FeCoFeO4 (inverse)NiO.Fe2O3 = FeNiFeO4 - (inverse)MgO.Fe2O3 = FeMgFeO4 (inverse)1.2.3 haphazard SPINELIt has an intermediate cation distribution, represented as B0.67 A0.33tet A0.67B1.33octO4.In this elemen tary unit cell of spinel structure consists eight tetrahedral and sixteen octahedral sites which are occupied by metal ions and the extreme cases, represent completely normal and inverse spinel, Therefore, the general cation distribution can be represented as M(2)iq+M(1)1-ip+AIV M(1)p+i/2 M(2)(2-i)/2q+2BvI O4where M+(1)p+ and M(2)q+ are the minority and majority cations respectively. Hence, the first quantity in brackets shows the come occupancy of A-sites (coordination number of four (IV)) and the second quantity in brackets shows the middling occupancy of B-sites (coordination number of six (VI)). The inversion parameter , shows the fraction of A-sites acquired by majority ions.