Kerr imaging of a thin film magnetic transducer to measure thin film head fields

In this work, the field generated by a magnetic recording head is measured by sensing the magnetization of a transducer film, placed in proximity to t he ABS of the head. The magnetization is measured by sensing Kerr rotation of a 250 mn laser spot scanned over the transducer at a step size of 55 rim . Since this measurement provides transducer normal magnetization, rather t han normal field, the associated head fields are computed by iteratively so lving the torque balance on the transducer magnetization and Laplace's equa tion. This yields a vector field consistent with the observed transducer ma gnetization and the transducer magnetization gradients. Using this techniqu e the fringing fields of a head with a 0.33 mum gap and a 2 mum trackwidth are measured.