Ryo Matsubara

Write field calculation for a narrow-track, single-pole head with a thin underlayer of perpendicular medium

The recording field of a narrow-track, single-pole (SPT) write head with a double-layered medium was investigated using three-dimensional eddy current transient finite element analysis. In the calculations, a soft-magnetic underlayer with a thickness of 100 nm was assumed. The results illustrate a large head field strength at a track width of 100 nm and a large recording field gradient at the trailing edge.

Finite-element model analysis of single-pole-type head for 1 Tbit/in/sup 2/

A three-dimensional (3-D) FEM simulation of a 1 Tbit/in/sup 2/ head/medium model has been carried out. Three new structures, side shields, a tapered main pole, and a tapered return path for the head have been introduced in order to produce a large recording field, a small stray field to the adjacent tracks, and a skew-effect-free field distribution, that are all indispensable for higher linear and higher track density recording. The proposed head structure gives sufficient head field strength and gradient for 1 Tbit/in/sup 2/ recording as described in previous literature, as well as a narrow pulse width.

New structured planar write head for 100 Gb/in/sup 2/ and beyond

A planar-type write head (proposed by Storage Research Consortium, Japan) for high-density longitudinal magnetic recording, is investigated by using transient finite-element analysis. First, conventional write heads are analyzed and the issue is discussed. Then, a planar-type write head is examined and possibilities (large recording field strength) and issues (large crosstrack field) are noted. Finally, head structure optimization using the finite-element method is carried out. Improving the crosstrack field has been realized at a small cost of reducing the on-track field. The obtained planar head has a large recording field, large recording field gradient, and less crosstrack field, all of which are suitable for higher density magnetic recording.

Numerical study of a narrow-track single-pole head useful for GHz response and large field strength requirements

The narrow-track single-pole (SPT) write head recording field was investigated using 3-D eddy current transient finite element analysis. After validating the finite element model for the SPT head with a double-layered medium, head field time variations were studied for various cases. Results show that a large head field strength reaching B/sub s/ of head pole at track width of 100 nm and high frequency response of 2 GHz.

Numerical analysis of narrow-track single-pole-type head with side shields for 1 Tb/in.2

To improve the performance of perpendicular magnetic recording using a single-pole-type (SPT) head and double-layered medium, a finite-element method simulation has been carried out with a calculation model for 1 Tb/in.2. Additional side shield poles have been introduced to reduce the side-writing field while maintaining the recording field strength. The side-writing ratio, assumed to be (field strength at adjacent track center)/(field strength at home track center), was 0.31 without the side shields. The optimized side shield allows this to be reduced to 0.11. A much narrower off-track field distribution than with conventional heads was obtained with the SPT head.

Recording field analysis of narrow-track SPT head with side-shields

Perpendicular recording of 107 Gb/in/sup 2/ demonstration has been carried out by the combination of single-pole head (SPT) and double-layered medium. In order to achieve higher areal densities, obtaining strong recording field in a narrow-track width in an SPT head is indispensable for both higher linear and track densities. In this paper, recording density of 1 Tb/in/sup 2/ is assumed and the recording field of an SPT head is investigated using 3-D FEM analysis. Side-yoke shields are set and the structure is optimized to reduce the side-writing field while maintaining the recording field strength.

Distribution of magnetic field strength inside exciting coil of single sheet tester

The double H-coil method was proposed to detect magnetic field strength on the surface of a specimen more accurately than the single H-coil method. In this paper, the distribution of magnetic field strength inside exciting coil of a single sheet tester (SST) is measured simultaneously by the single H-coil method using four separated H-coils. They are placed at different distances from the surface of the specimen and thereby enable us to evaluate the influence of the position of the H-coil on the measurement accuracy of magnetic properties. As a result, it was revealed that the magnetic field strength and specific total loss increase linearly as the distance of the H-coil from the surface of the specimen increases. However the increasing rate of the specific total loss is smaller than that of the magnetic field strength and within the range of required measurement reproducibility.

FEM analysis of single pole type head for 1 TBPSI recording

In this paper, FEM simulation was carries out to obtain an SPT head with large recording field, small stray and skew-effect-free field distribution.