Magnetic behaviour of nanocrystalline Ni0.5Cu0.5Fe2O4 spinel ferrite
The magnetic behaviour of the nanocrystalline Ni0.5Cu0.5Fe2O4, synthesized by the co-precipitation method has been studied. The X-ray diffraction patterns confirm the formation of cubic spinel structure. The dc magnetization measurements show that the sam
- PDF / 548,666 Bytes
- 7 Pages / 439.37 x 666.142 pts Page_size
- 46 Downloads / 220 Views
iginally published in the journal Hyperfine Interactions, Volume 184, Nos 1–3, 489–495. DOI: 10.1007/s10751-008-9769-7 © Springer Science + Business Media B.V. 2008
Abstract The magnetic behaviour of the nanocrystalline Ni0.5 Cu0.5 Fe2 O4 , synthesized by the co-precipitation method has been studied. The X-ray diffraction patterns confirm the formation of cubic spinel structure. The dc magnetization measurements show that the samples are superparamagnetic above the blocking temperatures and the blocking temperature increases with particle size. The reduction in saturation magnetization in the case of nanoparticles as compared to their bulk counterpart has been explained on the basis that the magnetic moments in the surface layers of a nanoparticle are in a state of frozen disorder. The hump in ZFC curve progressively shift to a lower temperature with increasing field and broader curves at higher field, suggests the spin-glass nature of the system. Keywords Nano-particles · Spinel ferrites · Superparamagnetism
1 Introduction Spinel ferrites have been extensively used for many kinds of magnetic devices such as transformers, inductors and magnetic heads for high frequency because their electrical resistivity is higher than that of the soft magnetic alloys. Several investigators have focused their attention on Ni–Cu ferrite because copper containing ferrites have interesting magnetic and electrical properties [1, 2]. Ni–Cu ferrites are preferred because of improved magnetic properties, high frequency response and high resistance. In the field of electronics, researchers continue to investigate the design of superstructures comprised of magnetically ordered arrays to enhance the
S. N. Dolia (B) · A. S. Prasad · M. S. Dhawan · M. P. Sharma Department of Physics, University of Rajasthan, Jaipur 302 004, India e-mail: [email protected] S. Chander Sobhasaria Engineering College, Sikar 332 021, India
N. S. Gajbhiye and S. K. Date, ICAME 2007. DOI: 10.1007/978-3-540-78696-2_64
489
490
S.N. Dolia et al.
sensitivity in magnetic sensors. The stability of electronic and high density data storage devices made by magnetic nanocomposites is limited by their superparamagnetic transition. Thus, while current efforts are aimed at increasing the thermal energy barrier against the magnetic reversal in magnetic nanocomposites, there is strong interest to understand the magnetization processes in the superparamagnetic region [3]. The present work has been taken up to study the magnetic behaviour of nanoparticles of Ni0.5 Cu0.5 Fe2 O4 prepared by chemical co-precipitation.
2 Experimental details A ferrofluid comprised of Ni0.5 Cu0.5 Fe2 O4 in the nano-size range has been prepared using a wet chemical process using oleic acid as surfactant and kerosene as the dispersing medium. In order to obtain a narrow distribution of particle sizes, the resulting fluid was centrifuged at 12,000 rpm. For obtaining dried particles of this ferrite, the carrier liquid from the ferrofluid has been removed by repetitive washing with acetone [4, 5]. Th
Data Loading...
