Relaxation processes of magnetite-based ferrofluids in rf magnetic fields

The components of the complex magnetic susceptibility of two ferrofluid samples, consisting of magnetite particles dispersed in kerosene, were determined within 1-100 MHz. The maximum values of the imaginary components, detected at 20 and 30 MHz, are associated with Neel relaxation. The experimental data were obtained using a new measuring technique based on the use of a short-circuited coaxial line, into which the ferrofluid was introduced.