Cu induced coercivity enhancement in the low viscosity GdCo5-xCux system

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)We investigate the influence of Cu substitution, on the coercivity and magnetic viscosity, in the ternary system GdCo5-xCux (x = 0, 0.5, 1, 1.5, 2 and 2.5) with different field sweep rates. All samples have been studied in the as cast state and crystallize in a single phase CaCu5 structure. With Cu addition, the coercivity was 10 times enhanced for x = 1.5. The behavior of the coercivity H-c against field sweep rate, dH/dt, shows that the GdCo5-xCux system exhibits only a small magnetic viscosity effect, a desirable property for magnetic dynamic applications under high magnetic field. (c) 2011 Elsevier B.V. All rights reserved.3231418901894Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPES [029-07

Study of A and B sites order in lanthanide-doped lead titanate ferroelectric system

International audiencePb(0.88)Ln(0.08)TiO(3) ferroelectric system, where Ln = La, Sm, Eu, and Dy, has been characterized using Scanning Electron Microscopy, Raman spectroscopy, and X-ray diffraction experiments. Softening of the lowest transverse optical phonon mode E (1TO) was evaluated as a function of the rare earths' ionic radius suggesting partial occupation of lanthanide ions at the A and B sites of the perovskite structure. Using Rietveld refinements, it has been established a higher incorporation of Ln(3+) ions into the A sites of the perovskite structure than that of the B sites for the studied ceramics. The occupation at B sites increases slightly with the decreases of the ionic radii of the lanthanides. (C) 2016 International Centre for Diffraction Data

Coercivity Behavior In Gd (co1-x Cux)5 System As Function Of The Microstructureevolution

Magnetic measurements, X-ray diffraction and scanning electron microscopy (SEM) experiments were carried out in the as-cast Gd(Co1-x Cux)5 samples with different Co/Cu content. Already in the as cast state, this system shows high coercive field for x=0.3 and a magnetization driven by nucleation of reversal domain. SEM micrograph and microanalysis show possible spinodal decomposition in the as-cast state, hence regions with different Co/Cu-content are observed, while the Gd-content almost does not change. High resolution X-ray diffraction patterns show a main CaCu5-type structure with traces of a secondary phase and distorted peak profiles as function of the Cu content. The evolution of the microstructure is discussed in relation with the Cu incorporation into the CaCu 5-type structure. The Cu addition avoids the formation of the 2:7 phase within the 1:5 matrix, favoring the formation of a more homogeneous Gd(Co,Cu)5 phase. The relation between the observed microstructure and the magnetic behavior is also discussed. © 2013 Elsevier B.V. All rights reserved.4146771Nesbitt, E.A., Willens, R.H., Shenvood, R.C., Buehler, E., Wernick, J.H., (1968) Appl. Phys. Lett., 12 (361)Hasegawa, R., Taylor, R.C., (1975) J. Appl. Phys., 46, p. 3606Senno, H., Tawara, Y., (1974) IEEE Trans. Magn., MAG-10 (2), p. 313Strnat, K.J., Rare earth-cobalt permanent magnets (1988) Handbook of Magnetic Materials, 4. , E.P. Wohlfarth, K.H.J. Buschow (Eds.) ElsevierHumar, K., (1988) J. Appl. Phys., 63 (6)Grössinger, R., Tellez-Blanco, J.C., Turtelli, R.S., Hauser, R., Reiterer, K., Sassik, H., Chouteau, G., (2001) Phys. B, 194, p. 294Seixas, T.M., Machado Da Silva, J.M., Braun, H.F., Eska, G., (2008) J. Appl. Phys., 103, pp. 07b720Seixas, T.M., Salgueiro Da Silva, M.A., Braun, H.F., Eska, G., (2009) J. Appl. Phys., 105, pp. 07E102Kuznetsova, Yu.V., Suponev, N.P., Degteva, O.B., Salev, P.S., (2011) J. Surf. Invest., 5-6, p. 1107Grechishkin, R.M., Kustov, M.S., Cugat, O., Delamare, J., Poulin, G., Mavrudieva, D., Dempsey, N.M., (2006) Appl. Phys. Lett., 89, p. 122505De Oliveira, L.A.S., Sinnecker, J.P., Grössinger, R., Pentón- Madrigal, A., Estévez-Rams, E., (2011) J. Magn. Magn. Mater., 323, p. 1890Hubbard, W.M., Adams, E., Gilfrich, J.V., (1960) J. Appl. Phys. Suppl., 31 (5)Uehara, M., (1980) J. Appl. Phys., 51, p. 5495Uehara, M., (1982) J. Appl. Phys., 53, p. 3730Shidlovsky, I., Wallace, W.E., (1970) J. Solid State Chem., 2, p. 193Chuang, Y.C., Wu, C.H., Chen, H.B., (1985) J. Less-Common Mater., 106, p. 41Estévez-Rams, E., Fidler, J., Pentón, A., Valor-Reed, A., Tellez-Blanco, J.C., Turtelli, R.S., Grössinger, R., (1999) J. Magn. Magn. Mater., 195, p. 595Espina-Hernandez, J.H., Lora-Serrano, R., Knobel, M., Sinnecker, E.H.C.P., De Oliveira, L.A.S., Sinnecker, J.P., Grössinger, R., Estévez-Rams, E., (2009) J. Phys. D Appl. Phys., 42, p. 125005Kahn, Y., (1974) Phys. Status Solidi A, 23 K151Pareti, L., Solzi, M., Marusi, G., (1992) J. Appl. Phys., 72 (7), p. 3009Allen, C.W., Lia, K.C., Miller, A.E., (1977) J. Less-Common Met., 52 (109)Pentón, A., Estévez, E., Lora, R., Espina-Hernandez, J.H., Grössinger, R., Valor-Reed, A., Turtelli, R.S., (2007) J. Alloys Compd., 429, p. 343Lectard, E., Allibert, C.H., Valignat, N., (1994) Proceedings of the Eighth International Symposium on Magnetic Anisotropy and Coercivity in RE-TM Alloys, p. 30

Coercivity behavior in Gd(Co1-xCux)(5) system as function of the microstructure evolution

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Magnetic measurements, X-ray diffraction and scanning electron microscopy (SEM) experiments were carried out in the as-cast Gd(Co1-xCux)(5) samples with different Co/Cu content. Already in the as cast state, this system shows high coercive field for x = 0.3 and a magnetization driven by nucleation of reversal domain. SEM micrograph and microanalysis show possible spinodal decomposition in the as-cast state, hence regions with different Co/Cu-content are observed, while the Gd-content almost does not change. High resolution X-ray diffraction patterns show a main CaCu5-type structure with traces of a secondary phase and distorted peak profiles as function of the Cu content. The evolution of the microstructure is discussed in relation with the Cu incorporation into the CaCu5-type structure. The Cu addition avoids the formation of the 2:7 phase within the 1:5 matrix, favoring the formation of a more homogeneous Gd(Co, Cu)(5) phase. The relation between the observed microstructure and the magnetic behavior is also discussed. (C) 2013 Elsevier B.V. All rights reserved.4146771Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)[XPD-11718]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPES [328/2011][XPD-11718

Evolution Of The Microstructure And Magnetic Properties Of Sm(co 0.6cu0.4)5 Alloys Prepared With Different Sm Excess Content

The structure of annealed Sm(Co0.6Cu0.4)5 compounds, prepared with different Sm excess content, has been investigated by means of high resolution x-ray diffraction and scanning electron microscopy. The samples were also magnetically characterized by thermomagnetic analysis and M versus H curves at room temperature. Increasing Sm excess improves the compositional order of the 1 : 5 phase. The coercivity (HC) and the Curie temperature (TC) are both changed as a function of Sm excess content. The decrease in the structural defects density, resulting from the compositional order, is responsible for the observed magnetic behaviour. © 2009 IOP Publishing Ltd.4212Gabay, A.M., Larson, P., Mazin, I.I., Hadjipanayis, G.C., (2005) J. Phys. D: Appl. Phys., 38 (9), pp. 1337-1341Pentón, A., Estévez, E., Lora, R., Espina-Hernndez, J.H., Grössinger, R., Turtelli, R.S., Valor-Reed, A., (2007) J. Alloys Compounds, 429 (1-2), pp. 343-347Liu, X., Zhao, H., Kubota, Y., Wang, J.P., (2008) J. Phys. D: Appl. Phys., 41 (23), p. 232002Hofer, F., (1970) IEEE Trans. Magn., 6 (2), p. 221Fähnle, M., Oesterreicher, H., (1983) J. Magn. Magn. Mater., 38 (3), pp. 331-335Téllez-Blanco, J.C., Grössinger, R., Turtelli, R.S., (1999) J. Alloys Compounds, 283 (1-2), pp. 289-295Téllez-Blanco, J.C., Grössinger, R., Turtelli, R.S., (1997) Proc. Workshop on High Coercivity MaterialsLectard, E., Allibert, C.H., Ballou, R., (1994) J. Appl. Phys., 75 (10), pp. 6277-6279Forner, S., McNiff, E.J., Oesterreicher, H., Parker, F.J., Misroch, M., (1978) J. Appl. Phys., 49 (3), pp. 2061-2063Barbera, B., Uehara, M., (1976) IEEE Trans. Magn., 12 (6), pp. 997-999Estévez-Rams, E., Fidler, J., Pentón, A., Téllez-Blanco, J.C., Turtelli, R.S., Grössinger, R., (1999) J. Alloys Compounds, 283 (1-2), pp. 327-330Estévez-Rams, A., Pentón, A., Novo, S., Fidler, J., Téllez-Blanco, J.C., Grössinger, R., (1999) J. Alloys Compounds, 283 (1-2), pp. 289-295Estévez-Rams, E., Fidler, J., Pentón, A., ValorRed, A., Téllez-Blanco, J.C., Turtelli, R.S., Grössinger, R., (1999) J. Magn. Magn. Mater., 195 (3), pp. 595-600Tang, W., Zhang, Y., Hadjipanayis, G.C., (2000) Appl. Phys. Lett., 77 (3), p. 421Tang, W., Zhang, Y., Hadjipanayis, G.C., (2003) J. Appl. Phys., 91 (10), p. 7896Schobinger, D., Gutfleisch, O., Hinz, D., Mueller, K.H., Schultz, L., Martinek, G., (2002) J. Magn. Magn. Mater., 242-245, p. 1347Kubish, M., Brown, N.D., Gutfleisch, O., Gebel, B., Mueller, K.H., Schultz, L., Harris, I.R., (2000) IEEE Trans. Magn., 36 (5), p. 3303Verma, A., Sidhu, R.K., Mahajan, S., Paney, O.P., (1996) J. Mater. Sci. Lett., 15 (23), p. 2088Teresiak, A., Kubis, M., Mattern, N., Wolf, M., Gruner, W., Mueller, K.H., (1999) J. Alloys Compounds, 292 (1-2), p. 212De Campos, M.F., Rios, P.R., (2004) J. Alloys Compounds, 377 (1-2), p. 121Grössinger, R., Wittig, E., Küpferling, M., Taraba, M., Reyne, G., Golovanov, C., Enzberg-Mahlke, B., Dudding, J., (1999) IEEE Trans. Magn., 35 (5), p. 3971Fidler, J., (1997) 11th Int. Conf. on Ternary and Multinary Compounds, ICTMC-11Lebail, A., Duroy, H., Fourquet, J.L., (1988) Mater. Res. Bull., 23 (3), p. 447Zhang, Y., Gabay, A., Wang, Y., Hadjipanayis, G.C., (2004) J. Magn. Magn. Mater., 272-276, pp. 1899-e1900De Campos, M.F., Okamura, H., Hadjipanayis, G.C., Rofrigues, D., Landgraf, F.J.G., Neiva, A.C., Romero, S.A., Missell, F.P., (2004) J. Alloys Compounds, 368 (1-2), pp. 304-307Gjoka, M., Kalogirou, O., Sarafidis, S., Niarchos, D., Hadjipanayis, G.C., (2002) J. Magn. Magn. Mater., 242-245, pp. 844-846Allen, C.W., Liao, K.C., Miller, E., (1977) J. Less-Common Met., 52 (1), p. 10

Evolution of the microstructure and magnetic properties of Sm(Co0.6Cu0.4)(5) alloys prepared with different Sm excess content

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The structure of annealed Sm(Co0.6Cu0.4)(5) compounds, prepared with different Sm excess content, has been investigated by means of high resolution x-ray diffraction and scanning electron microscopy. The samples were also magnetically characterized by thermomagnetic analysis and M versus H curves at room temperature. Increasing Sm excess improves the compositional order of the 1 : 5 phase. The coercivity (H-C) and the Curie temperature (T-C) are both changed as a function of Sm excess content. The decrease in the structural defects density, resulting from the compositional order, is responsible for the observed magnetic behaviour.4212EC [II0147FI]The LNLS at Campinas, Brazil [XRD 884/01]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)EC [II0147FI]The LNLS at Campinas, Brazil [XRD 884/01]CAPES [029-07