Measurements on Real and Imaginary Parts of Transverse Susceptibility of Particulate System

In this paper, the influence of ac field frequency on transverse susceptibility (TS) curves was investigated. Two different experimental setups were used to reach the excitation frequency of 6 GHz. At low frequencies, the real and imaginary parts of the susceptibility were directly obtained by measuring the impedance of a coil incorporating the sample using a RLC bridge. In the microwave frequency domain, the susceptibility was correlated with the scattering parameters of a transmission line containing the sample. The experimental data show that for a Ni-Zn ferrite polycrystalline sample Ni_0.65Zn_0.35Fe₂O₄ and for ac field frequencies up to 100 MHz, the TS peeks do not present an important shift in field positions. The measured real and imaginary parts of the TS have the same peek structure, but the amplitude and line width differ. At higher ac frequencies, the peeks field are frequency dependent and a supplementary peek was observed.