Abstract---A thin film magnetic head for perpendicular recording was developed by the combination of a single pole transducer and a low flying slider. FeZrN sputtered film with high saturation magnetization was employed as a main pole of the transducer and the slider was designed from fluid dynamics calculation to achieve very low flying height. The read/write characteristic of the head at 25 nm flying height using CoCrlNiFeNb media were 350 n Vp-p/ J.L m' m/s' turn at 15 kFCI and -34dB in overwrite. Performance of the head when combined with high Bs material for the main pole, high Hc and thin recording layer for the medium, and low flying height of the slider was discussed from the point of high density recording.

Abstract----The write head design for a merged MR head needs to be optimized to obtain a good wrIte performance for a perpendicular magnetic recording application. We fabricated a write-only single pole head with the simplified structure which consists of a main pole and a thin film coil without a return yoke. The write performance of the single pole head with double-layered media was evaluated by using an MR read head. The O/W value obtained was less than -35dB, and the PWso value obtained from the differentiated curve of the readback waveform was 0.20 J1 m. The small PWsofrom the recorded bits attributes to the sharp magnetic transitions.Key words: perpendicular magnetic recording, single pole head, simplified structure, write head, MR head, I . INTRODUCTIONPerpendicular magnetic recording is expected to be an important technology for high recording density. The areal density of lOGbitslin 2 and beyond was obtained experimentally, using a sjngle-pole head and a double-layered perpendicular medium [1]. The combination of an MR head and a double-layered medium is also a promising technology for future high-density recording [2]. Muraoka et.at. pointed out the 50% linear density(D50) of the roll-off curve measured by the MR head increased by 70% associating with the differential equalizer [3].If an MR head is used as a read element, a write head becomes simplified structure which consists of a main pole and a thin film coil, without a return yoke. It is because the recording process of a perpendicular magnetic recording single pole head on a double-layered medium is carried out through a main pole, a recording layer and an under-layer of the medium.It is considered that write head design should be optimized to obtain a good write performance of the merged MR head for perpendicular magnetic recording. In this study, we developed a simple structured write-only single pole head without the return yoke on the basis of analytical results from a computer simulation. The structure and write characteristics of the write-only single pole head when read out by the MR head are discussed. IT . EXPERIMENTALThe write magnetic field amplitude ofthe simplified singlepole head without a return yoke(Head A) was calculated using a three-dimensional finite element method, and that of the conventional single pole head(Head B) [4] was also calculated for comparison.The head was fabricated by a thin film process with the help of an analytical simulation. Electrical performances of the head were measured by a GUZIK read/write analyzer (RWA1601), and an MRhead was used as a read head at the flying height of 40nm.In order to investigate the write performance of Head A, we measured saturation characteristics for this head, and also measured for Head B as a reference. The roll-off curves and isolated waveforms when read by the MR head were measured for the following three cases concerning media and write heads. Case A; a longitudinal medium and a ring head, Case B; a perpendicular medium and a ring head, and Case C; a perpendicular medium a...

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