Temperature Dependence Of Magnetization Of Cobalt Ferrite (Cofe2o4)

Abstract

Now days, the studies of Nano particles of magnetic oxides have receive much attention because of their promising technological advantages for application in medicine, sensors, magnetic recordings, catalysts. Among wide range of ferrites nano particles Cobalt ferrite has attracted much attention as a hard magnetic material exhibiting a high coercivity. It also shows an enhanced saturation magnetization of about 80emu/g at room temperature and sizeable magneto crystalline anisotropy. A temperature dependent model is necessary in order to understand the behavior of magnetization process in ferromagnetic material at different temperatures. In the present study a physical model based on Jiles-Atherton (JA) theory was developed to study the effects of temperature on magnetic hysteresis Cobalt ferrite .This Thermal effects were incorporated through temperature dependent hysteresis parameters of the existing model, adding critical exponent and Curie temperature as additional parameters. The temperature dependent Jiles- Atherton (JA) model was validated against measurements On Cobalt ferrite and the result shows good agreement between theory and analytical method. The value of constant parameters in the temperature dependent of magnetization of measured data of cobalt ferrite with curie point of (Tc=793) starting from temperature ranges of 100k; and the critical exponent (𝛽1) was estimated to be 0.4from fitting the analytical model of spontaneous magnetization to be measured data while (𝛽2) and (𝛽3) are assumed to be (𝛽1/2) in pinning factor and domain density while ;they have same value with spontaneous magnetization in domain coupling and and reversibility factor. The relation between them is spontaneous magnetization, pinning factor, domain density, domain coupling are decreasing with temperature while reversibility factor increasing with temperature. Key words: Cobalt ferrite, magnetization, spontaneous, pinning factor, domain density, domain coupling and reversibility fac