Large frequency shift in Fe-based nanocrystalline powder cores

Resonance frequency fr of a LC circuit composed of a capacitor and a small solenoid, which contains Fe-based nanocrystalline powder cores, was measured. The properties of resonance frequency fr shift dependence on external magnetic field, Hex, have been investigated. The results showed that fr evidently increases with Hex and exhibits good linearity and sensitivity in the low field range. The large frequency shift is another form of giant magneto-impedance effect. The method can be used for measuring magnetic field or for improving the sensitivities of magnetic sensors