Patent ID: 8289017

Claim:
A method of analysing a magnetic material, comprising: a) excitation of the magnetic material simultaneously with: a low-frequency excitation magnetic field (H L ) of periods T L , the period T L comprising at least first and second period fractions such that the average of the instantaneous value of the low-frequency magnetic field over the first period fraction is different from the average of its instantaneous value over the second period fraction, each period fraction having a duration of at least 100 nanoseconds and a high-frequency excitation magnetic field (H H ), the variation of the instantaneous value of which over the course of time is periodic with a frequency f H , the frequency f H of the high-frequency excitation magnetic field being at least twice the frequency f L of the low-frequency magnetic field; b) the construction of a signature S(H) of the magnetic material formed from at least two points S(H) P , this construction including obtaining the value of each point S(H) P by measuring, over each period fraction, the amplitude and possibly the phase of a harmonic of the magnetic field induced in the magnetic material, said amplitude and phase being obtained in response to the excitation during this period fraction, the harmonic having a frequency nf H , where n is a non-zero positive integer; and c) the identification and/or the determination of the mass of the magnetic material from several points of the constructed signature S(H).