Microwave Characteristics (Reflection Losses) of Composite Materials Consisting of Magnetic Nanoparticles

Magnetic materials find numerous applications in various devices, such as absorbers in the mm range. Depending on their purpose, soft or hard magnetic materials are used in a bulk, film or composite form. The object of the work presented was to investigate the microwave (MW) absorbing properties of nanocomposite bulk samples. We used magnetite (Fe3O4) with a particle size of about 30 nm as a filler in a silicone rubber matrix and investigated the influence of an applied external magnetic field during the process of polymerization of the samples measuring the reflection losses in the frequency range of 1–20 GHz. It was found that the external magnetic field increased the reflection losses and slightly changed the matching frequencies at which they appeared.