Peculiarities of reflection of electromagnetic waves in the microwave range from magnetic colloids

Abstract

We have investigated experimentally the reflection of an electromagnetic (EM) wave in the microwave range at a frequency of 10.65 GHz from a layer of a magnetic fluid (magnetic colloid) and composites synthesized on its basis. It is found that, upon an increase in the solid-phase concentration, the conditions for the emergence of ferromagnetic resonance in the homogeneous magnetic colloid change. We have revealed peculiarities of reflection of an EM wave from the magnetic emulsion layer under the action of magnetic fields with a strength much smaller than that corresponding to the ferromagnetic resonance condition. The modulus of the coefficient of reflection from a five-layer system containing the magnetic emulsion has been calculated theoretically and compared with experimental values. In the same range of field strengths, we have investigated the reflection of an EM wave from the composite of a magnetic fluid and micrometer-size nonmagnetic bronze particles