Nanostructure And Giant Hall Effect In Tmx(sio2) 1-x (tm=co,fe,ni) Granular System

Granular TMx (Si O2) 1-x (TM=Co,Fe,Ni) thin films were thermally treated at different temperatures and their magnetotransport and structural properties were studied. Hall resistivity decreases with thermal annealing. Structure was analyzed based on small angle x-ray scattering results. A model of polydisperse system of hard spheres was used for obtaining structural parameters. Analysis reveals that a volume fraction of transition-metal atoms (less than 29%) are forming nanospheres. Changes in giant Hall effect upon annealing can depend on a particular combination of nanoparticle diameter, interparticle distance, and size distribution. © 2006 American Institute of Physics.998Pakhomov, A.B., Yan, X., Zhao, B., (1995) Appl. Phys. Lett., 67, p. 3497Denardin, J.C., Knobel, M., Zhang, X.X., Pakhomov, A.B., (2003) J. Magn. Magn. Mater., 262, p. 15Hurd, C.M., (1972) The Hall Effect in Metals and Alloys, , Plenum, New YorkZhang, X.X., Wan, C., Liu, H., Li, Z.Q., Sheng, P., Lin, J.J., (2001) Phys. Rev. Lett., 86, p. 5562Jing, X.N., Wang, N., Pakhomov, A.B., Fung, K.K., Yan, X., (1996) Phys. Rev. B, 53, p. 14032Aronzon, B.A., Granovskii, A.B., Kovalev, D.Y., Meilikhov, E.Z., Ryl'kov, V.V., Sedova, M.V., (2000) JETP Lett., 71, p. 469Wan, C.C., Sheng, P., (2002) Phys. Rev. B, 66, p. 075309Socolovsky, L.M., Denardin, J.C., Brandl, A.L., Knobel, M., (2003) Mater. Charact., 50, p. 117Robertus, C., Philipse, W.H., Joosten, J.G.H., Levine, Y.K., (1989) J. Chem. Phys., 90, p. 4482Svergun, D.I., Konarev, P.V., Volkov, V.V., Koch, M.H.J., Sager, W.F.C., Smeets, J., Blokhuis, E.M., (2000) J. Chem. Phys., 113, p. 1651Socolovsky, L.M., Oliveira, C.L.P., Denardin, J.C., Knobel, M., Torriani, I., (2005) Phys. Rev. B, 72, p. 18442

Magnetic And Magnetotransport Properties Of Nanostructured Magnetic Materials

The magnetic and magnetotransport properties of nanostructured magnetic materials were discussed. These materials were formed by magnetic grains, whose size was of the order of few nanometers, embedded in a matrix of a different magnetic phase. The analysis suggested the alteration of the microstructure of the nanocrystalline system by means of proper thermal treatments.403117126Vázquez, M., Hernando, A., (1995) Adv. Mater., 7, p. 1021Herzer, G., (1993) Phys. Scripta., T49, p. 307Hernando, A., Kulik, T., (1994) Phys. Rev. B, 49, p. 7064Randrianantoandro, N., Slawska-Waniewska, A., Greneche, J.M., (1997) Phys. Rev. B, 56, p. 10797Schmool, D.S., Garitaonandia, J.S., Barandiarán, J.M., (1998) Phys. Rev. B, 58, p. 12159Slawska-Waniewska, A., Roig, A., Molins, E., Greneche, J.M., Zuberek, R., (1997) J. Appl. Phys., 81, p. 4652Slawska-Waniewska, A., Gutowski, M., Lachowicz, H.K., Kulik, T., Matyja, H., (1992) Phys. Rev. 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Effects Of Dipolar Interactions On Magnetic Properties Of Granular Solids

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Structural, Magnetic And Transport Properties Of Discontinuous Granular Multi-layers

Results of structural, magnetic and transport properties of magnetic Co/SiO2 discontinuous multi-layers produced by sequential deposition are presented. Transmission electron microscopy (TEM) images show that the samples that are close to metal-insulation transition are composed by a connected network of metallic paths, and display an enhanced Hall Effect. The granular samples are composed by an almost periodic array of Co nanoparticles, and after annealing these samples show a clear evolution in the nanostructure, with increasing average Co grain sizes and decreasing size dispersion. Relationships between the nanostructure and magnetotransport properties are discussed and compared with previous results obtained in cosputtered films. © 2005 Elsevier B.V. All rights reserved.2942206212Abeles, B., Sheng, P., Coutts, M.D., Arie, Y., (1975) Adv. Phys., 24, p. 40Vázquez, M., Hernando, A., (1995) Adv. Mater., 7, p. 1021Herzer, G., (1993) Phys. Scripta T, 49, p. 307Hernando, A., Kulik, T., (1994) Phys. Rev. B, 49, p. 7064Denardin, J.C., Brandl, A.L., Knobel, M., Panissod, P., Pakhomov, A.B., Liu, H., Zhang, X.X., (2002) Phys. Rev. B, 65, p. 064422Milner, A., Gerber, A., Groisman, B., Karpovsky, M., Gladkikh, A., (1996) Phys. Rev. Lett., 76, p. 475Slawska-Waniewska, A., Gutowski, M., Lachowicz, H.K., Kulik, T., Matyja, H., (1992) Phys. Rev. B, 46, p. 14594Pakhomov, A.B., Yan, X., Zhao, B., (1995) Appl. Phys. Lett., 67, p. 3497Jing, X.N., Wang, N., Pakhomov, A.B., Fung, K.K., Yan, X., (1996) Phys. Rev. B, 53, p. 14032Denardin, J.C., Knobel, M., Pakhomov, A.B., Zhang, X.X., (2003) J. Magn. Magn. Mater., 262, p. 15Aronzon, B.A., Rylkov, V.V., Kovalev, D.Y., Meilikhov, E.Z., Ryl'Kov, V.V., Sedova, M.V., (2000) Phys. Stat. Solidi, 218, p. 169Aronzon, B.A., Granovskii, A.B., Kovalev, D.Y., Meilikhov, E.Z., Ryl'Kov, V.V., Sedova, M.V., (2000) JETP Lett., 71, p. 469Zhang, X.X., Wan, C.C., Liu, H., Li, Z.Q., Sheng, P., Lin, J.J., (2001) Phys. Rev. Lett., 86, p. 5562Wan, C.C., Sheng, P., (2002) Phys. Rev. B, 66, p. 075309Maurice, J.L., Briatico, J., Carrey, J., Petroff, F., Schelp, L.F., Vaures, A., (1999) Philos. Mag. A, 79, p. 2921Skumryev, V., Stoyanov, S., Zhang, Y., Hadjipanayis, G., Givord, D., Nogues, J., (2003) Nature, 423, p. 850L.M. Socolovsky, C.L.P. Oliveira, J.C. Denardin, M. Knobel, I.L. Torriani, unpublishedDa Silva, F.C.S., Ferrari, E.F., Knobel, M., (1998) J. Appl. Phys., 84, p. 5366Denardin, J.C., Knobel, M., Socolovsky, L.M., Brandl, A.L., Zhang, X.X., (2003) IEEE Trans. Magn., 39, p. 276