Determination of basic magnetic unit size in CoCrTa/Cr magnetic disk media

Author

Wong, Bunsen Y. ; Laughlin, David E.

Author_Institution

Dept. of Mater. Sci. & Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA

Volume

34

Issue

1

fYear

1998

fDate

1/1/1998 12:00:00 AM

Firstpage

293

Lastpage

298

Abstract

The magnetic transition region in a CoCrTa/Cr hard disk has been studied with high-resolution Foucault-mode Lorentz microscopy. It was found that the amplitude of the zigzag transition increases significantly at the track edges. Imaging results show that the CoCrTa grains behave magnetically in a clustered manner, forming domains of varying sizes at the transition. The dimension of the smallest grain cluster [or the basic magnetic unit (bmu)] has been determined by studying a pair of antiparallel domain contrast images in this medium, Investigations also reveal that each bmu consists of six to eight CoCrTa hcp grains, giving an average bmu unit size of about 80±12 mm. Furthermore, the magnetic domain images indicate that the mechanical texture induced by polishing does not break up this intergranular coupling

Keywords

chromium; chromium alloys; cobalt alloys; demagnetisation; ferromagnetic materials; grain size; hard discs; magnetic domains; magnetic recording noise; tantalum alloys; 68 to 92 nm; CoCrTa-Cr; Foucault-mode Lorentz microscopy; antiparallel domain contrast images; domain formation; grain cluster; hard disks; intergranular coupling; magnetic disk media; magnetic domain images; magnetic transition region; magnetic unit size; mechanical texture; track edges; zigzag transition; Chromium; Couplings; Demagnetization; Magnetic domains; Magnetic force microscopy; Magnetic noise; Magnetization; Magnetostatics; Materials science and technology; Uncertainty;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.650358

Filename

650358