Complex magnetic susceptibility measurement of a magnetic fluid magnetite based

In this work, we present the synthesis and measurement of complex magnetic susceptibility χ(ω) = χ'(ω) - χ"(ω) of a magnetite magnetic fluid, oleic acid-kerosene. Measurements were developed applying different magnetic polarising fields by means of an electromagnet. Short-circuited transmission line technique was used. Complex magnetic susceptibility measurements of magnetic fluids are presented as a function of both frequency and external polarising magnetic field in ranges from 60 MHz to 6 GHz and from 0 Oe to 1212 Oe, respectively. Resonance frequencies in the range from 2.09 GHz to 5.06 GHz and maximum frequencies in the range from 1.19 GHz to 4.68 GHz as a function of the bias polarising field were measured for the magnetic fluid. From resonance measurements for different polarising fields, a mean anisotropy field value of A= 767Oe was obtained. Also a mean value of anisotropy constant = 12.2x104erg/cm3 and gyromagnetic ratio γ = 16.07 x 106 1/sOe were determined.