Resolution of unshielded and shielded MR heads for perpendicular magnetic recording

To achieve the recording technology over 10 Gb/in(2), quite short bit cells have to be written and read probably by an MR head. The resolutions of unshielded and shielded MR heads were estimated for perpendicular and longitudinal recording. Moreover, we designed and fabricated some samples of the MR/Inductive heads that have been developed for perpendicular magnetic recording, and evaluated them with a double-layered medium. The shielded MR head offered high D-50 of 170 kFRPI and high-density readback signal of 500 kFRPI. However, when the recorded bit length became shorter than the MR-to-shield gap, the shield had little effect and the output of the shielded head was no longer roughly equal to that of the unshielded head. Even unshielded MR head has good high-density recording characteristics in case of the combination with a perpendicular medium.