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

An experimental study of the reflection of a microwave electromagnetic (EM) wave at a frequency of 10.65 GHz from a magnetic fluid layer (magnetic colloid) and composites synthesized on its basis has been carried out. It was found that with an increase in the concentration of the solid phase in a homogeneous magnetic colloid, the conditions for the occurrence of ferromagnetic resonance change. The features of the process of reflection of an EM wave from a layer of magnetic emulsion under the influence of magnetic fields, the intensity value of which is much less than the intensity corresponding to the condition of ferromagnetic resonance, are revealed. Theoretical calculations of the modulus of the reflection coefficient from a five-layer system containing a magnetic emulsion were carried out, followed by a comparison of their results with experimental data. In the same range of field strengths, the reflection of an EM wave from a layer of a composite of a magnetic fluid and non-magnetic particles of micron-sized bronze is investigated.