Magnetism in exposed and coated nanoclusters studied by dichroism in X-ray absorption and photoemission

被引:14
作者
Binns, C [1 ]
Baker, SH
Edmonds, KW
Finetti, P
Maher, MJ
Louch, SC
Dhesi, SS
Brookes, NB
机构
[1] Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England
[2] Univ Nottingham, Sch Phys & Astron, Nottingham NG7 2RD, England
[3] INFM, Lab TASC, Palazzina MM, I-34012 Basovizza, Italy
[4] ESRF, F-38043 Grenoble, France
关键词
nanoclusters; dichroism; nanomagnetism;
D O I
10.1016/S0921-4526(02)00804-9
中图分类号
O469 [凝聚态物理学];
学科分类号
070205 ;
摘要
We have studied the evolution of the magnetic behaviour of size-selected Fe nanoclusters from isolated particles adsorbed on a surface exposed in UHV to dense interacting assemblies. The Clusters were produced by a UHV-compatible gas aggregation source and were studied in situ by synchrotron radiation techniques based on dichroism. Isolated and exposed Fe clusters deposited on highly oriented pyrolitic graphite Substrates exhibit orbital and spin magnetic moments that are, respectively, tip to 250% and 10% higher than the values measured in thick Fe films. The moments decay towards the bulk value with increasing cluster size or with increasing particle density on the surface. The total moment in the supported clusters is not as high as observed in free clusters of the same size. The individual particles appear to be magnetically isotropic but a strong in-plane coherent anisotropy develops as the coverage is increased to a complete cluster monolayer. Coating the deposited Fe clusters with a Co film substantially increases the spin moment on the Fe. (C) 2002 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:350 / 359
页数:10
相关论文
共 32 条
[1]   The construction of a gas aggregation source for the preparation of size-selected nanoscale transition metal clusters [J].
Baker, SH ;
Thornton, SC ;
Edmonds, KW ;
Maher, MJ ;
Norris, C ;
Binns, C .
REVIEW OF SCIENTIFIC INSTRUMENTS, 2000, 71 (08) :3178-3183
[2]   Macroscopic quantum tunneling in molecular magnets [J].
Barbara, B ;
Thomas, L ;
Lionti, F ;
Chiorescu, I ;
Sulpice, A .
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 1999, 200 (1-3) :167-181
[3]  
Barbara B, 2000, J PHYS SOC JPN, V69, P383
[4]   MAGNETIC-MOMENTS OF IRON CLUSTERS WITH 25 TO 700 ATOMS AND THEIR DEPENDENCE ON TEMPERATURE [J].
BILLAS, IML ;
BECKER, JA ;
CHATELAIN, A ;
DEHEER, WA .
PHYSICAL REVIEW LETTERS, 1993, 71 (24) :4067-4070
[5]   Synchrotron radiation studies of mass-selected Fe nanoclusters deposited in situ [J].
Binns, C ;
Baker, SH ;
Maher, MJ ;
Thornton, SC ;
Louch, S ;
Dhesi, SS ;
Brookes, NB .
EUROPEAN PHYSICAL JOURNAL D, 2001, 16 (1-3) :189-192
[6]  
BINNS C, 2001, UNPUB PHYS REV LETT
[7]   SURFACE EFFECTS IN METALLIC IRON NANOPARTICLES [J].
BODKER, F ;
MORUP, S ;
LINDEROTH, S .
PHYSICAL REVIEW LETTERS, 1994, 72 (02) :282-285
[8]   X-RAY CIRCULAR-DICHROISM AND LOCAL MAGNETIC-FIELDS [J].
CARRA, P ;
THOLE, BT ;
ALTARELLI, M ;
WANG, XD .
PHYSICAL REVIEW LETTERS, 1993, 70 (05) :694-697
[9]   EXPERIMENTAL CONFIRMATION OF THE X-RAY MAGNETIC CIRCULAR-DICHROISM SUM-RULES FOR IRON AND COBALT [J].
CHEN, CT ;
IDZERDA, YU ;
LIN, HJ ;
SMITH, NV ;
MEIGS, G ;
CHABAN, E ;
HO, GH ;
PELLEGRIN, E ;
SETTE, F .
PHYSICAL REVIEW LETTERS, 1995, 75 (01) :152-155
[10]   Macroscopic quantum coherence in a magnetic nanoparticle above the surface of a superconductor [J].
Chudnovsky, EM ;
Friedman, JR .
PHYSICAL REVIEW LETTERS, 2000, 85 (24) :5206-5209