Document Type
Article
Publication Date
2008
Journal or Book Title
Journal of Applied Physics
Volume
103
Issue
7
First Page
07E506
DOI
10.1063/1.2832503
Abstract
The temperature dependence of magnetization, magnetic anisotropy, and coercive field of gallium-substituted cobaltferrite was investigated for a series of compositions of CoGaxFe2−xO4 (0⩽x⩽0.8). Hysteresis loops were measured for each sample over the range of −5T⩽μ0H⩽5T for selected temperatures between 10 and 400K. The magnetization at 5T and low temperatures was found to increase for the lower Ga contents (x=0.2 and 0.4) compared to pure CoFe2O4, indicating that at least initially, Ga3+substitutes predominantly into the tetrahedral sites of the spinel structure. The high field regions of these loops were modeled using the law of approach to saturation, which represents the rotational process, together with an additional linear forced magnetization term. The first order cubic magnetocrystalline anisotropy coefficient K1 was calculated from curve fitting to these data. It was found that K1 decreased with increasing Ga content at all temperatures. Both anisotropy and coercivity increased substantially as temperature decreased. Below 150K, for certain compositions (x=0, 0.2, 0.4), the maximum applied field of μ0H=5T was less than the anisotropy field and, therefore, insufficient to saturate the magnetization. In these cases, the use of the law of approach method can lead to calculated values of K1 which are lower than the correct value.
Rights
Copyright 2008 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Copyright Owner
American Institute of Physics
Copyright Date
2008
Language
en
File Format
application/pdf
Recommended Citation
Ranvah, N.; Melikhov, Y.; Jiles, David C.; Snyder, J. E.; Moses, A. J.; Williams, P. I.; and Song, S. H., "Temperature dependence of magnetic anisotropy of Ga-substituted cobalt ferrite" (2008). Materials Science and Engineering Publications. 98.
https://lib.dr.iastate.edu/mse_pubs/98
Comments
The following article appeared in Journal of Applied Physics 103 (2008): 07E506 and may be found at http://dx.doi.org/10.1063/1.2832503.