Magneto-resonance frequency shift study of Fe-based nanocrystalline powder cores

The complex permeability spectra were measured in Fe-based nanocrystalline powder core. Magneto-resonance frequency shift (MFS) of a LC circuit, which is composed of a small solenoid with the powder cores inside and a capacitor connected in parallel, has also been investigated. The results showed that the sensitivity of the MFS with respect to external magnetic field related to magnetic properties of the powder cores. The circuit included the powder core annealed at 600 °C is most sensitive to external magnetic field. The phenomena are discussed by classical electromagnetic theory and thinking about the magnetic dipole interaction between the grains. The MFS can be regarded as one type of giant magneto-impedance effect.