Effects of Pt addition on the magnetic and microstructural properties of CoC granular films

Author

Delaunay, J.-J. ; Hayashi, T. ; Tomita, M. ; Hirono, S.

Author_Institution

NTT Integrated Inf. & Energy Syst. Labs., Tokyo, Japan

Volume

34

Issue

4

fYear

1998

fDate

7/1/1998 12:00:00 AM

Firstpage

1627

Lastpage

1629

Abstract

The magnetic properties and microstructures of granular Co_60-XPt_XC₄₀ (0⩽x⩽23) thin films, fabricated by ion-beam sputtering and subsequent annealing, were investigated. High coercivity was obtained in samples with Pt concentrations ranging from 12 to 16 atomic percent, with a maximum coercivity of 1800 oersteds. These films consisted of CoPt grains having a CoPt disordered alloy phase, which were separated by a C phase. The magnetic grains had an average size of 10 nm and a faulted hexagonal close-packed structure. Below 16 at.% Pt content, the improvement in coercivity with Pt was most likely related to an increase in the magnetocrystalline anisotropy of the CoPt alloy compared to that of the Co. Above 16 at.% Pt content, a drastic decrease in coercivity was observed. It is found that for these large Pt concentrations a higher annealing temperature is required to improve the coercivity with Pt addition

Keywords

cobalt alloys; coercive force; crystal microstructure; grain size; magnetic anisotropy; magnetic thin films; platinum alloys; sputtered coatings; 10 nm; Co_60-XPt_XC₄₀; CoC granular films; CoPt disordered alloy phase; CoPt grains; CoPtC; annealing; faulted hexagonal close-packed structure; ion-beam sputtering; magnetic grains; magnetocrystalline anisotropy; maximum coercivity; Anisotropic magnetoresistance; Annealing; Coercive force; Magnetic anisotropy; Magnetic films; Magnetic properties; Magnetic separation; Microstructure; Perpendicular magnetic anisotropy; Sputtering;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.706637

Filename

706637