Synthesis Of Ag-cofe2o4 Dimer Colloidal Nanoparticles And Enhancement Of Their Magnetic Response

This paper reports the structural and magnetic properties of Ag-CoFe 2O4 colloidal dimer nanoparticles (NPs) synthesized using a two-step solution-phase route. Ag NPs were used as seeds to grow Ag-CoFe 2O4 dimer NPs using thermal decomposition of metallic precursor. By means of temperature and field dependent dc magnetization measurements, it is found that the silver due to its interface with CoFe 2O4 particles leads to thermal stabilization of the dimer NPs superior as compared to CoFe2O4 alone. Our results show enhancement of the magnetic anisotropy and a large coercivity at 2 K for dimer NPs, which could be ascribed to interface effect between Ag and CoFe 2O4 components and the related structural defects. © 2011 American Institute of Physics.1097Sun, Y., Xia, Y., Shape-controlled synthesis of gold and silver nanoparticles (2002) Science, 298 (5601), pp. 2176-2179. , DOI 10.1126/science.1077229Wang, C., Wei, Y., Jiang, H., Sun, S., (2009) Nano Lett., 9, p. 4544. , 10.1021/nl903077tLopes, G., Vargas, J.M., Sharma, S.K., Beron, F., Pirota, K.R., Knobel, M., Rettori, C., Zysler, R.D., (2010) J. Phys. Chem. C, 114, p. 10148. , 10.1021/jp102311uHori, H., Yamamoto, Y., Ywamoto, T., Miura, T., Teranishi, T., Miyake, M., (2004) Phys. Rev. B, 69, p. 174411. , 10.1103/PhysRevB.69.174411Jordan, A., Scholz, R., Wust, P., Fahling, H., Felix, R., (1999) J. Magn. Magn. Mater., 201, p. 413. , 10.1016/S0304-8853(99)00088-8Goya, G.F., Grazu, V., Ibarra, M.R., Magnetic nanoparticles for cancer therapy (2008) Current Nanoscience, 4 (1), pp. 1-16. , http://www.ingentaconnect.com/content/ben/cnano/2008/00000004/00000001/ art00001, DOI 10.2174/157341308783591861Yu, H., Chen, M., Rice, P.M., Wang, S.X., White, R.L., Sun, S., Dumbbell-like bifunctional Au-Fe3O4 nanoparticles (2005) Nano Letters, 5 (2), pp. 379-382. , DOI 10.1021/nl047955qPeddis, D., Cannas, C., Piccaluga, G., Agostinelli, E., Fiorani, D., (2010) Nanotechnology, 21, p. 125705. , 10.1088/0957-4484/21/12/125705Desjonquéres, M.C., Barreteau, C., Autés, G., Spanjaard, D., (2007) Phys. Rev. B, 76, p. 024412. , 10.1103/PhysRevB.76.024412Salazar-Alvarez, G., Olsson, R.T., Sort, J., Macedo, W.A.A., Ardisson, J.D., Baro, M.D., Gedde, U.W., Nogues, J., Enhanced coercivity in co-rich near-stoichiometric CoxFe 3-xO4+δ nanoparticles prepared in large batches (2007) Chemistry of Materials, 19 (20), pp. 4957-4963. , DOI 10.1021/cm070827