System and method for non-destructive measurement of dynamic coercivity effects

A method for non-destructive measurement of dynamic coercivity of magnetic media, the magnetic media initially having a substantial number of aligned magnetic moments, the method comprising the steps of:

• applying a first number of reversed magnetic field pulses at a fixed magnetic field intensity to the magnetic media and measuring broadband medium noise of the magnetic media for each of a number of incrementally increasing magnetic field intensities;
• deriving the coercivity of the magnetic media from the magnetic field intensity at which the broadband medium noise is approximately at a maximum;
• and
• repeating the above steps while varying the first number of reversed magnetic field pulses.

A system for non-destructive measurement of dynamic coercivity of magnetic media initially having a substantial number of aligned magnetic moments, the system comprising:

• a write head for applying a first number of reversed magnetic field pulses at a first magnetic field intensity to the magnetic media for each of a number of incrementally increasing first magnetic field intensities;
• a read head for reading an information signal from the magnetic media after each application of the first number of reversed magnetic field pulses;
• a frequency analysis device responsive to the information signal from the read head for generating a Fourier spectrum from the information signal read from the magnetic media after each application of the first number of reversed magnetic field pulses;
• and
• a computing device in communication with the frequency analysis device for computing a broadband medium noise value from the Fourier spectrum generated after each application of the first number of reversed magnetic field pulses, and determining coercivity of the magnetic media as a function of the first number of reversed magnetic field pulses by locating the first magnetic field intensity at which the broadband medium noise value is approximately at a maximum;
• wherein the dynamic coercivity of the magnetic media may be observed by varying the first number of reversed magnetic field pulses and determining the coercivity of the magnetic media as a function of the first number of reversed magnetic field pulses.