Dependence of side-erasing effect and core efficiency on side taper angle of high Bs metal in gap head

• Published in: Journal of applied physics 1997-04, Vol.81 (8), p.4492-4494
• Main Authors: Itoh, Takahiko, Kobayashi, Hiroshi, Ozeki, Tatsuo
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.364988

The side-erasing effect is a very serious problem, especially in guardband-less recording systems with a narrow track pitch (e.g., 10 μm pitch of consumer digital VCRs). We report the dependence of side-erasing effect and output voltage on the oblique side taper plane angle of high Bs (Fe–Zr–N) metal in gap (MIG) heads. We measured the side-erasing width written by several kinds of MIG heads (gap length=0.21 μm, track width=14 μm, gap depth=12 μm) with various side taper angles (45°, 60°, and 90°) between the gap plane and the side taper plane on metal evaporated tapes and on two types of particulate tapes. Measurement conditions were 10.2 m/s relative velocity, 2 μm wave length, and 720, 960, and 1750 Oe Hc tapes. The side-erasing width decreases with increasing side taper angle in the MIG head or with increasing tape Hc. The difference between the side-erasing width for a 60° and a 90° head is small. However, the output voltage decreases with increasing side taper angle. The normalized output voltage of 45° head at 20.4 MHz is superior 0.58 and 2.38 dB to the 60° and 90° head, respectively. Simulation results of the side-fringing field and the core efficiency using a three-dimensional finite element method, incorporating the decreasing of Fe–Zr–N permeability on tilted substrates, indicate a similar trend to the experimental results. The 60° side taper angle MIG head is more suitable than the 45° and 90° heads for high density and guardband-less recording, because it is a good compromise between output voltage and side-erasing width.