Competing interactions in dispersions of superparamagnetic nanoparticles

被引：141

作者：

Held, GA ^{[1
]}

Grinstein, G ^{[1
]}

Doyle, H ^{[1
]}

Sun, SH ^{[1
]}

Murray, CB ^{[1
]}

机构：

[1] IBM Corp, Thomas J Watson Res Ctr, Yorktown Hts, NY 10598 USA

来源：

PHYSICAL REVIEW B | 2001年 / 64卷 / 01期

关键词：

D O I：

10.1103/PhysRevB.64.012408

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We study the magnetic properties of dispersions of uniformly sized, chemically synthesized cobalt nanoparticles (NP's), observing a crossover from a blocked state to a superparamagnetic one with increasing temperature. By analyzing magnetization data, we determine the distributions of NP volumes and anisotropies, and establish that variations in the shapes of the magnetic cores of the NP's generate the anisotropy governing the crossover. We characterize the frustrated low-temperature state produced by the competition between dipolar interactions and anisotropy at sufficiently high NP density through remanent magnetization measurements, and explain the results through analysis of a simple model.

引用

页数：4

共 23 条

[11] AGING IN A MAGNETIC PARTICLE SYSTEM
JONSSON, T
MATTSSON, J
DJURBERG, C
KHAN, FA
NORDBLAD, P
SVEDLINDH, P
[J]. PHYSICAL REVIEW LETTERS, 1995, 75 (22) : 4138 - 4141
[12] Static scaling on an interacting magnetic nanoparticle system
Jonsson, T
Svedlindh, P
Hansen, MF
[J]. PHYSICAL REVIEW LETTERS, 1998, 81 (18) : 3976 - 3979
[13] Size effect on the crystal phase of cobalt fine particles
Kitakami, O
Sato, H
Shimada, Y
Sato, F
Tanaka, M
[J]. PHYSICAL REVIEW B, 1997, 56 (21): : 13849 - 13854
[14] Landau L., 1935, PHYS Z SOWJETUNION, V8, P101, DOI DOI 10.1016/B978-0-08-036364-6.50008-9
[15] DIPOLE INTERACTIONS WITH RANDOM ANISOTROPY IN A FROZEN FERROFLUID
LUO, WL
NAGEL, SR
ROSENBAUM, TF
ROSENSWEIG, RE
[J]. PHYSICAL REVIEW LETTERS, 1991, 67 (19) : 2721 - 2724
[16] Blocking and freezing of magnetic moments for iron nitride fine particle systems
Mamiya, H
Nakatani, I
Furubayashi, T
[J]. PHYSICAL REVIEW LETTERS, 1998, 80 (01) : 177 - 180
[17] Colloidal synthesis of nanocrystals and nanocrystal superlattices
Murray, CB
Sun, SH
Gaschler, W
Doyle, H
Betley, TA
Kagan, CR
[J]. IBM JOURNAL OF RESEARCH AND DEVELOPMENT, 2001, 45 (01) : 47 - 56
[18] Neel L., 1949, Ann. Geophys. (C.N.R.S.), V5, P99, DOI DOI 10.1016/S0009-2509(00)00427-9
[19] The initial susceptibility in the FC and ZFC magnetisation processes
Papusoi, C
Stancu, A
Dormann, JL
[J]. JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 1997, 174 (03) : 236 - 246
[20] Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices
Sun, SH
Murray, CB
Weller, D
Folks, L
Moser, A
[J]. SCIENCE, 2000, 287 (5460) : 1989 - 1992

← 1 2 3 →