Spectrum of Barkhausen noise for periodic magnetisation of ferromagnetic materials in bulk

A technique was developed to isolate the Barkhausen noise resulting from the cyclic magnetisation of transformer cores; spectral and total noise measurements were made for silicon-iron, nickel-iron and ferrite samples. The results are analysed in the light of theoretical work, which hitherto lacked adequate experimental evidence, and an empirical formula is developed relating the spectral-power density and the magnetising frequency. The total noise obtained by the integration of this formula agrees closely with the measured value. Some consideration is given to the structure of the noise when treated as a succession of voltage impulses randomly dispersed about periodic positions within a framework of fixed zeros. These zeros coincide with the instants of reversal of the magnetising field.