Structural and magnetic study of a dilute magnetic semiconductor: Fe doped CeO2 nanoparticles

This paper reports the effect of Fe doping on the structure and room temperature ferromagnetism of CeO2 nanoparticles. X-ray diffraction and selective area electron diffraction measurement reflects that Ce1-xFexO2 (x = 0.0 - 0.07) nanoparticles exhibit single phase nature with cubic structure and none of the sample showed the presence of any secondary phase. The mean particle size calculated by using a transmission electron microscopy measurement was found to increase with increase in Fe content. DC magnetization measurements performed at room temperature indicates that all the samples exhibit ferromagnetism. The saturation magnetic moment has been found to increase with an increase in the Fe content.Comment: 16 Pages, 5 figure, 1 Table, Accepted in JN

Room temperature ferromagnetism in chemically synthesized ZnO rods

We report structural and magnetic properties of pure ZnO rods using X-ray diffraction (XRD), magnetization hysteresis (M-H) loop and near edge x-ray fine structure spectroscopy (NEXAFS) study at O K edge. Sample of ZnO was prepared by co-precipitation method. XRD and selective area electron diffraction measurements infer that ZnO rods exhibit a single phase polycrystalline nature with wurtzite lattice. Field emission transmission electron microscopy, field emission scanning electron microscopy micrographs infers that ZnO have rod type microstructures with dimension 200 nm in diameter and 550 nm in length. M-H loop studies performed at room temperature display room temperature ferromagnetism in ZnO rods. NEXAFS study reflects absence of the oxygen vacancies in pure ZnO rods.Comment: 8 Pages, 3 Figure

Kondo lattice model with a direct exchange interaction between localized moments

We study the Kondo lattice model with a direct antiferromagnetic exchange interaction between localized moments. Ferromagnetically long-range ordered state coexisting with the Kondo screening shows a continuous quantum phase transition to the Kondo singlet state. We obtain the value of the critical point where the magnetizations of the localized moments and the conduction electrons vanish. The magnetization curves yield a universal critical exponent independent of the filling factors and the strength of the interaction between localized moments. It is shown that the direct exchange interaction between localized moments introduces another phase transition from an antiferromagnetic ordering to a ferromagnetic ordering for small Kondo exchange interaction. We also explain the local minimum of the Kondo temperature in recent experiments.Comment: 6 pages, 5 figures, final versio

Boronated porphyrins in NCT: Results with a new potent tumor localizer

Several chemical methods are available for the solubilization of boronated porphyrins. We have previously reported the tumor localization of nido carboranyl porphyrins in which the icosahedral carborane cages have been opened to give B/sub 9/C/sub 2/ anions. One of these species has shown tumor boron levels of nearly 50 ..mu..g B/g when delivered by week-long subcutaneous infusions. We report here recent in vivo experiments with a new, highly water-soluble porphyrin based on the hematoporphyrin-type of compound in which aqueous solubility is achieved using the two propionic acid side chains of the ''natural'' porphyrin frame. 7 refs

Engineering Structural And Magnetic Properties Of Mgo.95mn O.o5fe2o4 Thin Films Using 200 Mev Au Ions

Pulsed laser deposited thin films of Mgo.95Mn o.05Fe2O4 ferrite were irradiated by 200 MeV Au14+ with a maximum dose up to 1 × 1012 ions/cm2. The as-deposited and irradiated thin films are investigated using X-ray diffraction (XRD), Raman Spectroscopy, Field emission electron microscopy (FESEM) and dc magnetization measurements. XRD and Raman spectroscopy measurements reflect the cubic spinel structure of films before and after irradiation. FESEM measurements demonstrate that films are composed of nano rods and nanocrystalline grains. Magnetic hysteresis loop measurements reveal that all the films have ferrimagnetic ordering at room temperature with enhancement in the coercive field and remnant magnetization due to irradiation. © 2009 The Ceramic Society of Japan. All rights reserved.1171365685688Brabers, V.A.M., (1995) Handbook of Magnetic Materials, 8. , Ed. by K. H. J. Buschow, Elsevier, AmsterdamBhargava, S.C., Zeman, N., (1980) Phys. Rev. B, 21, p. 1717Muralidharan, K., Srivastava, J.K., Moratha, V.R., Vijayaraghavan, R.J., (1985) Phys. C, 18, p. 5897Brand, R.A., Lauer, J., Herlach, D.M., (1984) J. Phys, F14Dormann, J.L., Nogues, M., (1990) J. Phys. Condense Matter, 2, p. 1223Dormann, J.L., Harfaouni, M.E.I., Nogues, M., Love, J., (1987) J. Phys. C, 20, pp. L161Thompson, M.W., (1969) Defects and Radiation Damage in Metals, , Cambridge University Press, CambridgeNeumeier, J.J., Hundley, M.F., Thompson, J.D., Heffner, R.H., (1995) Phys. Rev. B, 52, pp. R7006Ogale, A.S., Shinde, S.R., Kulkarni, V.N., Higgins, J., Choudhary, R.J., Kundaliya, D.C., Polleto, T., Venkatesan, T., (2004) Phys. Rev. B, 69, p. 235101S. B. Ogale, K. Ghosh, J. Y. Gu, R. Shreekala, S. R. Shinde, M. Downes, M. Rajeswari, R. P. Sharma, R. L. Green, TVenkatesan, Ramesh, R., Bathe, R., Patil, S.I., Kumar, R., Arora, S.K., Mehta, G.K., (1988) J. Appl. Phys, 84, p. 6255Sharma, S.K., Kumar, R., Kuma, V.V.S., Knobel, M., Reddy, V.R., Gupta, A., Singh, M., (2006) Nucl. Instr. and Meth. in Phys. Res. B, 248, pp. 37-11S. Kumar, S. K. Sharma, R. J. Alimuddin, D. M. Choudhary, Phase and R. Kumar, Nucl. Instr. and Meth. in Phys. Res. B, 266, 1741-1748 (2008)Studer, F., Toulmonde, M., (1992) Nucl. Instrum. Methods, B, 65, p. 560Houpert, C., Studer, F., Groult, D., Toulmonde, M., (1989) Nucl. Instrum. Methods B, , 39, 720Y723R. Kumar, S. B. Samantra, S. K. Arora, A. Gupta, D. Kanjilal, R. Pinto and A. V. Narlikar, Solid State Commun., 106[12], 805Y810 (1998)Kumar, R., Arora, S.K., Kanjilal, D., Mehta, G.K., Bache, R., Date, S.K., Shinde, S.R., Patil, S.I., (1999) Radiat. Eff. Defects Solids, 147, p. 187Komine, T., Mitsui, Y., Shiikj, K., (1995) J. Appl. Phys, 78 (12), p. 7220Turilli, G., Baooluzi, A., Lutennti, M., Tareti, L., (1992) J. Magn. Magn. Mater, 104-107, p. 114

Structural And Magnetic Properties Of Bulk And Thin Films Of Mg0.95mn0.05fe2o4

We present here a comparative study on structural and magnetic properties of bulk and thin films of Mg0.95Mn0.05Fe2O4 ferrite deposited on two different substrates using X-ray diffraction (XRD) and dc magnetization measurements. XRD pattern indicates that the bulk sample and their thin films exhibit a polycrystalline single phase cubic spinel structure. It is found that the film deposited on indium tin oxide coated glass (ITO) substrate has smaller grain size than the film deposited on platinum coated silicon (Pt-Si) substrate. Study of magnetization hysteresis loop measurements infer that the bulk sample of Mg0.95Mn0.05Fe2O4 and its thin film deposited on Pt-Si substrate shows a well-defined hysteresis loop at room temperature, which reflects its ferrimagnetic behavior. However, the film deposited on ITO does not show any hysteresis, which reflects its superparamagnetic behavior at room temperature. © 2008 Elsevier B.V. All rights reserved.9510091013Alvarado, S.F., (1979) J. Phys. B, 33, p. 51Shinjo, T., Kiyama, M., Sugita, N., Watanabe, K., Takada, T., (1983) J. Magn. Magn. Mater., 35, p. 33Nakano, M., Akase, M., Fukunaga, H., Matsuo, Y., Yabukami, S., Yamaguchi, M., Arai, K.I., (2002) J. Magn. Magn. Mater., 242-245, pp. 57-159Nakano, M., Tomohara, K., Song, J.M., Fukunaga, H., Matsuo, Y., (1999) IEEE Trans. Magn., 35 (5), p. 3007Nakano, M., Tomohara, K., Song, J.M., Fukunaga, H., Matsuo, Y., (2000) J. Appl. Phys., 87 (9), p. 6217Nakano, M., Tomohara, K., Song, J.M., Fukunaga, H., Matsuo, Y., (2000) IEEE Trans. Magn., 36 (5), p. 2927Canale, L., Girault, C., Bessaudou, A., Celerier, A., Cosset, F., Decossas, J.L., Vareille, J.C., (2000) Appl. Surf. Sci., 154-155, pp. 444-448Caltun, O.F., (2004) J. Optoelectron. Adv. Mater., 6 (3), p. 935Williams, C.M., Abe, M., Itoh, T., Lubitz, P., (1994) IEEE Trans. Magn., 30 (6), p. 4896Samarasekara, P., rani, R., Cadieu, F.J., Shaheen, S.A., (1996) J. Appl. Phys., 79, p. 8Papian, W.N., (1995) Proceeding of Metal Powder Association London, 2, p. 183Heck, C., (1974) Magnetic Materials and their Applications, , Butterworth, LondonKumar, S., Alimuddin, Kumar, R., Dogra, A., Reddy, V.R., Banerjee, A., (2006) J. Appl. Phys., 99, pp. 08M910Dong, C., (1999) J. Appl. Cryst., 32, p. 838Dash, J., Prasad, S., Venkataramani, N., Krishnan, P., Kumar, N., Kulkarani, S.D., Date, S.K., (1999) J. Appl. Phys., 86 (6), p. 3303Cullity, B.D., (1957) Elements of X-ray Diffraction, , Addision-Wesley, London p. 261Desai, M., Dash, J., Samajdar, I., Venkataramani, N., Prasad, S., Krishan, P., Kumar, N., (2001) J. Magn. Magn. Mater., 231, p. 08Stichauer, L., Gavoille, Z., Simsa, G., (1996) J. Appl. Phys., 79, p. 3645Lisfi, A., Guyot, M., Krishnan, R., Porte, M., Rougier, P., Cagan, V., (1996) J. Magn. Magn. Mater., 157-158, p. 258Kittel, C., (1946) Phys. Rev., 70, p. 965Kittel, C., (1948) Phys. Rev., 73, p. 810Cullity, B.D., (1972) Introduction to Magnetic Materials, , Addision-Wesley, New York p 386Kumar, V., Rana, A., Yadav, M.S., Pant, R.P., (2008) J. Magn. Magn. Mater., 320, p. 1729Sorescu, M., Diamandesca, Swaminathan, R., Mchenry, M.E., Fedar, M., (2005) J. Appl. Phys., 97, pp. 10G105Choi, H.S., Kim, M.H., Kim, H.J., (1994) J. Mater. Res., 9, p. 242