Nanorods; sol-gel; TEM; magnetic properties; dielectric behavior.
1Department of Physics, Eternal University, Baru Sahib, Sirmour (H.P.) 173101, India
2National Physical Laboratory, New Delhi 110012, India
3Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India
Adv. Mater. Lett., 2012, 'ICNANO 2011', 3 (6), pp 511-514
Publication Date (Web): Sep 23, 2012
Copyright © IAAM-VBRI Press
In the present work, the self-assembly of Co2+ and Fe3+ doped SnO2 nanoparticles (Co and Fe = 5 mol% each) into nanorods by co-doping of Ce3+ (4 mol%) ions is studied. The nanorods are prepared by a chemical route using polyvinyl alcohol as surfactant with the composition Sn0.91Co0.05Ce0.04O2 (SCC54) and Sn0.91Fe0.05Ce0.04O2 (SFC54). The X-ray diffraction (XRD), transmission electron microscopy (TEM), magnetic and electrical measurements are used to characterize these nanorods. The XRD pattern show the tetragonal rutile and polycrystalline nature of SnO2 nanorods which is also confirmed by TEM. The TEM images exhibit that the diameter of SCC54 nanorods lie in the range of 15-20 nm, length~100-200 nm whereas for SFC54 specimen, diameter ~5-15 nm and length ~50-100 nm. In our previous work, we fabricated Co and Fe (3 and 5 mol% each) doped SnO2 nanoparticles which exhibited high ferromagnetism. It is observed that on Ce3+ co-doping, nanoparticles assembled themselves into rod like structures and the values of saturation magnetization and dielectric properties have further enhanced. Thus the nature and the concentration of dopants are found to play crucial role in tuning the morphology, magnetic and electrical properties of nanostructures. The values of saturated magnetization (Ms) are 1.14 and 0.14 emu/g and coercive field are 112 and 42 Oe, in SCC54 and SFC54 specimen, respectively, at room temperature. The variation in dielectric behavior is attributed due to the interface polarization. However, in lower frequency regime, the decreasing trend of dielectric permittivity with increasing frequency is explained by the Maxwell-Wagner theory and Koops’ model, whereas, in higher frequency region, the resonant behavior is observed due to nano size effect.
Nanorods, sol-gel, TEM, magnetic properties, dielectric behavior.