Frequency losses of readback efficiency for thin-film inductive heads

Magnetic recording measurements on a rigid disk are used to derive the readback efficiency of thin film inductive heads as a function of frequency. The technique relies on a pseudo-contact air bearing system which keeps the transducer in contact with the disk over a range of velocities. It is found that the readback efficiency decreases monotonically with frequency, showing a 3 dB loss at 40 MHz for the heads used in this experiment. A four section transmission line model has been developed to include the geometry variations in different areas of the head. Domain wall motion and rotational contributions to flux transmission have been included. The calculated efficiency and impedance values are found to be in good agreement with measured values.