in the magnetic field. Bulk metals do not heat up in either the E or H field, as shown in
Figure 4.4(k) for solid copper.
However, the results for copper powder and iron oxide (Fe3O4) compacts are contrary to
the general assumptions. FeO and Fe2O3 oxide display typical characteristics similar to other
ceramic oxides; that is, they respond to the electric field component and heating is due to
dielectric losses. For Fe3O4, rapid heating was observed in both E and H microwave fields
but a higher temperature was achieved in the H field.