Abstract
We report on the direct observation of the intrinsic magnetization behavior of Mackay icosahedral Au nanoparticles. The spin arrangements in 3.5-nm icosahedral Au particles are found to be ferrimagnetic-like, where the core and surface moments point in opposite directions, with a net spontaneous magnetic moment of 16 μB per particle. The unpaired spins behave as J = 1/2 quantum spins. The average level separation is found to be a factor of ~1.53 larger than that estimated according to the Kubo formula for spherical Au particles. This reflects the fact that there are considerably fewer atoms packed in a particle with an icosahedral geometry than with a spherical one.
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References
Ashcroft NW, Mermin ND (1976) Solid State Physics. Saunders College, Philadelphia, pp 288–293
Caudillo R, Gao X, Escudero R, Jose-Yacaman M, Goodenough JB (2006) Ferromagnetic behavior of carbon nanospheres encapsulating silver nanoparticles. Phys Rev B 74:214418. doi:10.1103/PhysRevB.74.214418
Chang CM, Chou MY (2004) Alternative low-symmetry structure for 13-atom metal clusters. Phys Rev Lett 93:133401. doi:10.1103/PhysRevLett.93.133401
Craik D (1995) Magnetism-principles and applications. John Wiley & Sons, NY, pp 99–100
Crespo P, Litrán R, Rojas TC, Multigner M, de la Fuente JM, Sánchez-López JC, García MA, Hernando A, Penadés S, Fernández A (2004) Permanent magnetism, magnetic anisotropy, and hysteresis of thiol-capped gold nanoparticles. Phys Rev Lett 93:87204. doi:10.1103/PhysRevLett.93.087204
Garitaonandia JS, Insausti M, Goikolea E, Suzuki M, Cashion JD, Kawamura N, Ohsawa H, de Muro IG, Suzuki K, Plazaola F, Rojo T (2008) Chemically induced permanent magnetism in Au, Ag, and Cu nanoparticles: localization of the magnetism by element selective techniques. Nano Lett 8:661–667. doi:10.1021/nl073129g
Halperin WP (1986) Quantum size effects in metal particles. Rev Mod Phys 58:533–606. doi:10.1103/RevModPhys.58.533
Harbola MK, Sahni V (1988) Structure of the Fermi hole at surfaces. Phys Rev B 37:745–754. doi:10.1103/PhysRevB.37.745
Harris JGE, Grimaldi JE, Awschalom DD, Chiolero A, Loss D (1999) Excess spin and the dynamics of antiferromagnetic ferritin. Phys Rev B 60:3453–3456. doi:10.1103/PhysRevB.60.3453
Hori H, Yamamoto Y, Iwamoto T, Miura T, Ternishi T, Miyake M (2004) Diameter dependence of ferromagnetic spin moment in Au nanocrystals. Phys Rev B 69:174411. doi:10.1103/PhysRevB.69.174411
Huang Y-L, Chan KC, Wu SY, Lin C-I, Yeh S-F (2008) Size-effect induced short-range magnetic ordering in germanium nanoparticles. J Nanosci Nanotechnol (in press)
Juretschke HJ (1953) Exchange potential in the surface region of a free-electron metal. Phys Rev 92:1140–1144. doi:10.1103/PhysRev.92.1140
Kittel C (1996) Introduction to solid state physics, 7th edn. John Wiley & Sons, NY, pp 455–456
Li W-H, Wu SY, Yang CC, Lai SK, Lee KC, Huang HL, Yang HD (2002) Thermal contraction of Au nanoparticles. Phys Rev Lett 89:135504. doi:10.1103/PhysRevLett.89.135504
Mackay AL (1962) A dense non-crystallographic packing of equal spheres. Acta Crystallogr 15:916–918. doi:10.1107/S0365110X6200239X
Mørup S, Frandsen C (2004) Thermoinduced magnetization in nanoparticles of antiferromagnetic materials. Phys Rev Lett 92:217201. doi:10.1103/PhysRevLett.92.217201
Mørup S, Hansen BR (2005) Uniform magnetic excitations in nanoparticles. Phys Rev B 72:024418. doi:10.1103/PhysRevB.72.024418
Pereiro M, Baldomir D (2005) Determination of the lowest-energy structure of Ag8 from first principles calculations. Phys Rev A 72:45201. doi:10.1103/PhysRevA.72.045201
Pereiro M, Baldomir D, Arias JE (2007) Unexpected magnetism of small silver clusters. Phys Rev A 75:063204. doi:10.1103/PhysRevA.75.063204
Wang Y, Teitel S, Dellago C (2005) Melting of icosahedral gold nanoclusters from molecular dynamics simulations. J Chem Phys 122:214722. doi:10.1063/1.1917756
Xu C, Li ZY, Hui PM (2001) Monte Carlo studies of hysteresis curves in magnetic composites with fine magnetic particles. J Appl Phys 89:3403. doi:10.1063/1.1348326
Yamamoto Y, Miura T, Suzuki M, Kawamura N, Miyagawa H, Nakamura T, Kobayashi K, Teranishi T, Hori H (2004) Direct observation of ferromagnetic spin polarization in gold nanoparticles. Phys Rev Lett 93:116801. doi:10.1103/PhysRevLett.93.116801
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This research was supported by grants from the National Science Council of Taiwan, under Grant Nos. NSC 95-2112-M-008-039-MY3 and NSC 96-2112-M-259-008.
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Wu, CM., Li, CY., Kuo, YT. et al. Quantum spins in Mackay icosahedral gold nanoparticles. J Nanopart Res 12, 177–185 (2010). https://doi.org/10.1007/s11051-009-9592-3
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DOI: https://doi.org/10.1007/s11051-009-9592-3