A method to measure the magnetic field of a writer was developed. The method provides at least three interesting measurements of the magnetic field of the writer: 1) the spatial profile, 2) the saturation curve, and 3) the temporal profile. These measurements provide valuable information in discerning different writer designs. Challenges remain because 1) the spacing between the sensor and the writer is larger than the spacing between the recording head and media in a hard drive and 2) the sensors response is symmetric around zero, resulting in very peculiar responses when pulsing the coil drive current from negative peak to positive peak current. For this reason, only results for zero to peak pulses have been reported here.
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