Effect of atomic ordering on magnetization decay and activation volume of FePt nanoparticles

Author

Sakuma, Hiroshi ; Nishio, Hiroaki ; Kitamoto, Yoshitaka ; Yamazaki, Yohtaro ; Yamamoto, Hiroshi

Author_Institution

Dept. of Innovative & Eng.ed Mater., Tokyo Inst. of Technol., Yokohama, Japan

Volume

39

Issue

5

fYear

2003

Firstpage

2758

Lastpage

2760

Abstract

The magnetic viscosity of two kinds of FePt nanoparticles with different order parameters (0.66 and 0.99) is investigated. Although the sample with the lower order parameter showed greater magnetization decay than that with higher order parameter, the decay was much smaller than that of a Co-Cr longitudinal thin-film medium with areal density capability of 40 Gb/si. The two FePt samples had almost the same value of activation volume (∼5 × 10^-19 cm³) at around their coercivities in spite of the differences in the order parameter and the physical volume of the nanoparticles; their activation volume was equal to or smaller than their physical volume.

Keywords

coercive force; ferromagnetic materials; iron alloys; magnetic aftereffect; magnetic particles; magnetic recording; nanoparticles; platinum alloys; Co-Cr longitudinal thin-film medium; FePt; FePt nanoparticles; activation volume; areal density; atomic ordering; coercivities; magnetic viscosity; magnetization decay; order parameters; physical volume; Anisotropic magnetoresistance; Annealing; Assembly; Coercive force; Magnetic anisotropy; Magnetization; Nanoparticles; Perpendicular magnetic anisotropy; Thermal stability; X-ray scattering;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2003.815590

Filename

1233208