Control of Microstructure and Magnetic Properties of FePt Films With TiN Intermediate Layer

Author

Dong, K.F. ; Li, Hai Helen ; Hu, Jiang Feng ; Peng, Y.G. ; Ju, G. ; Chow, G.M. ; Chen, Jim S.

Author_Institution

Dept. of Mater. Sci. & Eng., Nat. Univ. of Singapore, Singapore, Singapore

Volume

49

Issue

2

fYear

2013

fDate

Feb. 2013

Firstpage

668

Lastpage

674

Abstract

The effects of a TiN intermediate layer on the microstructure and magnetic properties of the FePt films were investigated. It was found that the TiN layer could effectively block the diffusion of Cr into the FePt film. The good epitaxial relationships among these layers were revealed from the transmission electron microscopy (TEM) results. With introducing TiN intermediate layer the chemical ordering and magnetic properties of FePt films significantly improved. The FePt film with 5 nm TiN exhibited a high perpendicular coercivity of 13.7 kOe and a low in-plane coercivity of 0.24 kOe, resulting from the combined contribution of TiN (200) orientation, TiN layer roughness and the effective block of Cr diffusion. Moreover, with doping C into the FePt-SiN_x films, the out-of-plane coercivity increased due to the decrease of the exchange coupling, the grain size of FePt films decreased, and well-separated FePt grains and uniform size were formed. By optimizing the sputtering process, the [FePt (4 nm)-SiN_x 40 vol·% ]- 20 vol·% C (001) film with coercivity higher than 21.5 kOe, a single layer structure, and small FePt grain size of 5.6 nm in average diameter was obtained, which are suitable for ultrahigh density perpendicular recording.

Keywords

carbon; chromium; coercive force; doping; exchange interactions (electron); grain size; iron alloys; magnetic epitaxial layers; metallic epitaxial layers; platinum alloys; semiconductor materials; silicon compounds; sputter deposition; surface diffusion; surface roughness; titanium compounds; transmission electron microscopy; C doping; Cr diffusion; FePt films; FePt-SiN_x:C; FePt:Cr-TiN; TEM; TiN (200) orientation; TiN layer roughness; chemical ordering; epitaxial layers; exchange coupling; grain size; in-plane coercivity; intermediate layer; magnetic properties; microstructure; perpendicular coercivity; single layer structure; size 4 nm; size 5 nm; sputtering process; transmission electron microscopy; ultrahigh density perpendicular recording; Coercive force; Grain size; Magnetic anisotropy; Magnetic hysteresis; Magnetic properties; Microstructure; Tin; FePt films; TiN intermediate layer; microstructure; perpendicular media;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2012.2223204

Filename

6416981