  A low-cost and simple setup for measuring the high-frequency hysteresis loops
of magnetic samples is described. An AMF in the range 6-100 kHz with amplitude
up to 80 mT is produced by a Litz wire coil. The latter is air-cooled using a
forced-air approach so no water flow is required to run the setup.
High-frequency hysteresis loops are measured using a system of pick-up coils
and numerical integration of signals. Reproducible measurements are obtained in
the frequency range of 6-56 kHz. Measurement examples on ferrite cylinders and
on iron oxide nanoparticle ferrofluids are shown. Comparison with other
measurement methods of the hysteresis loop area (complex susceptibility,
quasi-static hysteresis loops and calorific measurements) is provided and shows
the coherency of the results obtained with this setup. This setup is well
adapted to the magnetic characterization of colloidal solutions of MNPs for
magnetic hyperthermia applications.
