| In this work, the field generated by a magnetic recording head is measured by sensing the magnetization of a transducer film that is placed in proximity to the ABS of the head. The magnetization is measured by sensing Kerr rotation of a 250 nm diameter laser spot as it is scanned over the transducer with a step size of 55 nm. Since this measurement provides transducer normal magnetization, rather than normal field, the associated head fields are computed by iteratively solving the torque balance on the transducer magnetization and Laplace's equation. This yields a vector field consistent with the observed transducer magnetization and the transducer magnetization gradients. Using this technique the fringing fields of a head with a 0.330 μm gap and a 2 μm trackwidth have been measured.; The head field can be calculated provided that the transducer used is thin enough such that the magnetic properties of the transducer do not cause substantial error to the applied head fields by influencing the magnetization in the recording head, but thick enough so that any light that may transmit through it and reflect back to the detector is attenuated sufficiently so as not to add a ‘false’ signal. In addition, awareness of the subtleties of Laplace's equation and the fast Fourier transform (FFT) is necessary as they are used extensively in this study. |
