MAGNETO DIELECTRIC BEHAVIOR OF THE MAGNETIC FLUID MANGANESE FERRITE IN CARBON-TETRACHLORIDE

This work concerns the research on ferrofluids or magnetic liquids, Fa st changes of their dielectric properties, which may be induced by pha se transitions of the carrier liquid or by aggregates or multi-layers forming, require the whole automation of the measurement process. Ther efore, we have used a high impedance programmable adaptor working on s hunt mode in the frequency range 1 mHz-10 kHz. It allowed us to charac terize, between + 50 degrees C and - 200 degrees C, an ionic ferroflui d made from nanometric particles of manganese ferrite (Fe2MnO4) dilute d at different concentrations in carbon tetrachloride (CCl4) used as c arrier liquid. We have pointed out the different phases of pure CCl4 ( liquid, plastic and solid). In our experimental conditions, we have sh own the lack of the ferrofluid stability at low temperature and high c oncentration. In addition, a magneto dielectric anisotropy is observed when a continuous magnetic field (parallel or perpendicular to the el ectric field) is applied.