Chemically synthesized FePt nanoparticle material for ultrahigh-density recording

被引：20

作者：

Kodama, H ^{[1
]}

Momose, S ^{[1
]}

Sugimoto, T ^{[1
]}

Uzumaki, T ^{[1
]}

Tanaka, A ^{[1
]}

机构：

[1] Fujitsu Labs Ltd, Atsugi, Kanagawa 2430197, Japan

来源：

IEEE TRANSACTIONS ON MAGNETICS | 2005年 / 41卷 / 02期

关键词：

easy axis; heat-treated FePt nanoparticles; magnetic field; M-H loops; surface reduction;

D O I：

10.1109/TMAG.2004.838050

中图分类号：

TM [电工技术]; TN [电子技术、通信技术];

学科分类号：

0808 ; 0809 ;

摘要：

We have examined the magnetic anisotropy of the "heat-treated FePt nanoparticles" annealed in a magnetic field. The magnetic easy axis of the "heat-treated FePt nanoparticles" is found to be three-dimensional (3-D) random and a partial ordering fct structure is observed before annealing in the presence of a magnetic field. The value of M-r/M-s obtained is 0.5. After annealing in the presence of a magnetic field, the M-H loop indicates that the easy axis is oriented preferably in the perpendicular direction than along the in-plane direction. The value of H-c(//) /H-c (perpendicular to) at 10 K is 0.62 (1410 Oe/2250 Oe). The value of M-r/M-s(perpendicular to) is 0.58 at 10 K larger than the value of M-r/M-s(//). Therefore, a weak magnetic easy axis orientation is fundamentally possible on the chemically synthesized FePt nanoparticles. We have studied the recording characteristics of a 3-D random nanoparticle medium using a GUZIK spinstand and observed the recorded patterns for the medium by imaging with a magnetic force microscopy.

引用

页码：665 / 669

页数：5