High frequency inductance measurements and performance projections made for cusp-field single pole heads

As the rigid disk drive industry has progressed to higher RPM to improve access times via latency reduction, the need for higher performance write and read channel electronics as well as heads has arisen. It appears that perpendicular recording is becoming a next generation candidate as a result of its advantage over longitudinal recording in the area of thermal stability. It is the ultimate frequency response of the head impedance that we wish to explore in this paper and measurements of the high frequency inductance can be used to provide considerable insight into the potential performance of recording heads. The cusp-field single pole head has several unique features that make it worthy of study. This paper is based upon the experimental procedure of first characterizing the head alone followed by the inclusion of the medium and its underlayer. Finally, frequency response comparisons are made between a commercial longitudinal recording head and several low turn cusp-field heads. The conclusions provide a practical bit rate limit for the cusp-field head based on the modeling results, experimental high frequency inductance data, and spin reversal.