Researchers are taking great interest in the synthesis and characterization of MnZn ferrites due to their wide range of applications in many areas. MnZn ferrites are a class of soft magnetic materials that have very good electrical, magnetic and optical properties. The properties of MnZn ferrites include high value of resistivity, permeability, permittivity, saturation magnetization, low power losses and coercivity. The above mentioned advantageous features of MnZn ferrites make them suitable for the use in various applications. In biomedical field these ferrites are used for cancer treatment and MRI. MnZn ferrites are also used in electronic applications for making transformers, transducers and inductors. These ferrites are also used in magnetic fluids, sensors and biosensors. MnZn ferrite is highly useful material for several electrical and electronic applications. It finds applications in almost every household appliances like mobile charger, LED bulb, TV, refrigerator, juicer mixer, washing machine, iron, microwave oven, mobile, laptop, desktop, printer and so on. Therefore, the present review focuses on different techniques for synthesis of MnZn ferrites in literature, their characterization tools, effect of doping on the properties of MnZn ferrite and finally we will discuss about their applications.

64, 980 (1986).The ' 2 5~e ~o s s b a u e r and nmr spectra of the compounds (R3X)2Te (R = Me, X = C, Si, Ge, and Sn; R = Ph, X = Ge and Sn), R3MTePh (R = Me, X = Si, Ge, and Sn; R = Ph, X = Ge, Sn, Pb), R2Sn(TePh)2 (R = Me and t-Bu), and thecyclic compounds (Me2SnTe)3, (Me2Sn)3Te2, and ( t -B~~s n T e )~ have been measured. The trends in the Mossbauer and nmr data are discussed. The Mossbauer quadrupole splittings increase as the nmr chemical shifts become more positive, corresponding to a decrease in the shielding at the tellurium nucleus. The '19Sn Mossbauer and nmrparameters of the compounds (R3Sn)2E and R3SnEPh (R = Me and Ph), (Me2SnE)3, (Me2Sn)2E2, (~-B U~S~E )~, and Me2Sn(EPh)2 (E = S, Se, and Te) are discussed. The l19sn Mossbauer quadrupole splittings are again observed to increase as the nmr chemical shifts become more positive. The I2'~e and '19sn nmr and Mossbauer data provide evidence that there is little transmission of bonding effects through the tin-tellurium bond as the chemical environment about the tin or tellurium is changed. C. H . W. JONES, R. D. SHARMA et S. P. TANEJA. Can. J. Chem. 64, 980 (1986). On a mesurC les spectres de Mossbauer et de rmn du 1 2 5~e des composts suivants: (R3X)2Te dans lesquels R = Me et X = C, Si, Ge et Sn ou R = Ph et X = Ge et Sn; R3MTePh dans lesquels R = Me et X = Se, Ge et Sn ou R = Ph et X = Ge, Sn et Pb; R2Sn(TePh)2 dans lesquels R = Me et t-Bu ainsi que les composts cycliques (Me2SnTe)3, (Me2Sn),Te2 et ( t -B~~s n T e )~. On discute des tendances qui se manifestent dans les donnCes relatives aux spectres de rmn et de Mossbauer. Les couplages quadrupolaires de Mossbauer augmentent lorsque les deplacements chimiques de la rmn deviennent plus positifs; ceci correspond ?i une diminution du blindage au niveau du noyau du tellure. On discute des param5tres de la rmn et des spectres de Mossbauer des composCs (R3Sn)2E et R3SnEPh dans lesquels R = Me et Ph ainsi que dans les composCs (Me2SnE)3, (Me2Sn)2E2, (t-Bu2SnE), et Me2Sn(EPh)2 dans lesquels E = S, Se et Te. Encore une fois dans ces cas, on observe que les couplages quadrupolaires dans les spectres de Mossbauer du '19sn augmentent lorsque les dkplacements chimiques de la rmn deviennent plus positifs. Les donnts de la spectroscopie de Mossbauer et de la rmn du 1 2 5~e et dh 'l9sn mettent en tvidence que les effets de liaison ne sont que faiblement ou peu transmis ?i travers la liaison Ctain-tellure lorsque change I'enviromement chimique autour de 1'Ctain ou du tellure.[Traduit par la revue]

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Recommended by R. N. P. ChoudharyAluminum doped manganese ferrites MnAl x Fe 2−x O 4 with 0.0 ≤ x ≤ 1.0 have been prepared by the double ceramic route. The formation of mixed spinel phase has been confirmed by X-ray diffraction analysis. The unit cell parameter 'a O ' is found to decrease linearly with aluminum concentration due to smaller ionic radius of aluminum. The cation distributions were estimated from Xray diffraction intensities of various planes. The theoretical lattice parameter, X-ray density, oxygen positional parameter, ionic radii, jump length, and bonds and edges lengths of the tetrahedral (A) and octahedral (B) sites were determined. 57 Fe Mössbauer spectra recorded at room temperature were fitted with two sextets corresponding to Fe 3+ ions at A-and B-sites. In the present ferrite system, the area ratio of Fe 3+ ions at the A-and B-sites determined from the spectral analysis of Mössbauer spectra gives evidence that Al 3+ ions replace iron ions at B-sites. This change in the site preference reflects an abrupt change in magnetic hyperfine fields at A-and B-sites as aluminum concentration increases, which has been explained on the basis of supertransferred hyperfine field. On the basis of estimated cation distribution, it is concluded that aluminum doped manganese ferrites exhibit a 55% normal spinel structure.

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