Atomic ordering reation and associated variation of magnetic coercivity of oriented L1₀-Fept nanoparticles

Sato, Kazuhisa; Bian, Bo; Hirotsu, Yoshihiko

Journal of Ceramic Processing Research, 2000, 1(2), 109-114

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Identifier to cite or link to this item: https://hdl.handle.net/11094/89452

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Title
Atomic ordering reation and associated variation of magnetic coercivity of oriented L1₀-Fept nanoparticles
Creator
NRID
1000070314424 1000070314424
ORCID
0000-0001-9078-2541 0000-0001-9078-2541
researchmap permalink
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Scopus Author ID
55552977400 55552977400
CreatorName
Sato, Kazuhisa
NRID
1000080283810 1000080283810
CreatorName
Bian, Bo
NRID
1000070016525 1000070016525
CreatorName
Hirotsu, Yoshihiko
Subject
Atomic ordering
L1₀-FePt
Amorphous Al₂O₃
HRTEM
Hard magnetism
High-density recording
Thermal fluctuation
Remanent magnetization decay
Abstract
Atomically ordered FePt nanoparticles (L10-type structure) covered with amorphous (a-) Al2O3 have been fabricated. In this process, Fe particles were deposited on Pt “seed” particles which were epitaxially grown on (100) NaCl or MgO substrates. Annealing the a-Al2O3/Fe/Pt films at temperatures higher than 773 K leads to a formation of ordered nanoparticles with mutual fixed orientation in a monolayer form. Three variant ordered domains of the tetragonal L10 structure coexisted in a single nm-sized FePt particle, even in a particle as small as 7 nm. According to in-situ electron diffraction study, the degree of order of the ordered structure started to increase on annealing at 773 K and almost saturated on annealing at 873 K for 16 h. The magnetic coercivity varied depending on the particle size and the degree of order in the L10 structure formation. The perpendicular coercivity exceeded the in-plane one during the annealing. The in-plane coercivities of FePt nanoparticles measured both parallel to [100]MgO and [010]MgO directions were almost equal in numerical value. These results reflect the ordered domain formation process and the volume fraction of the domains. Remanent magnetization decay measured for the in-plane magnetization revealed a magnetic relaxation with the type of magnetic dipolar interaction between the FePt particles.
Publisher
International Organization for Ceramic Processing
Source Title
Journal of Ceramic Processing Research
Volume (Issue)
1(2)
Page
109-114
Date of Issued
2000-12-31
Language
English
Handle URL
https://hdl.handle.net/11094/89452
PISSN
12299162
eISSN
2672152X
NCID
AA12173362
Access Rights
open access
CopyRight
This article is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
oaire:version
Version of Record
Category
学術雑誌論文 Journal Article