Thermal stability and SNR of coupled granular/continuous media

Author

Sonobe, Y. ; Weller, D. ; Ikeda, Y. ; Schabes, M. ; Takano, K. ; Zeltzer, G. ; Yen, B.K. ; Best, M.E. ; Greaves, S.J. ; Muraoka, H. ; Nakamura, Y.

Author_Institution

IBM Almaden Res. Center, San Jose, CA, USA

Volume

37

Issue

4

fYear

2001

fDate

7/1/2001 12:00:00 AM

Firstpage

1667

Lastpage

1670

Abstract

We investigated coupled granular/continuous (CGC) perpendicular media consisting of a continuous multilayer for high thermal stability and a granular host layer to reduce noise. The addition of Co/Pt multilayers increased the nucleation field of the CoCr₁₈Pt ₁₂ medium from 0 to -2000 Oe. Moreover, the moment decay was reduced from 4.8% to 0.1% per decade. Compared to Co/Pd multilayer media, the CGC medium had a 10 dB higher signal-to-noise ratio (SNR). The granular host layer significantly improved the SNR in the high-density region over 10 kfc/mm. Compared to the CoCr₂₀Pt ₁₀ medium, the CGC medium had a 3 dB higher SNR in the low-density region. The medium noise for the CGC medium increased with the recording density, while the noise for the CoCr₂₀Pt₁₀ medium remained constant from 10 to 20 kfc/mm. The approach using CGC medium improves both the SNR and the thermal stability

Keywords

chromium alloys; cobalt; cobalt alloys; magnetic multilayers; perpendicular magnetic recording; platinum; platinum alloys; thermal stability; Co-Pt-CoCr₂₀Pt₁₀; CoCr₁₈Pt₁₂; SNR; continuous multilayer; coupled granular/continuous media; granular host layer; high thermal stability; high-density region; nucleation field; recording density; reduce noise; signal-to-noise ratio; thermal stability; Anisotropic magnetoresistance; Coercive force; Magnetic heads; Magnetic multilayers; Magnetic noise; Magnetization; Noise reduction; Nonhomogeneous media; Signal to noise ratio; Thermal stability;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.950932

Filename

950932