RT Journal Article
T1 Permanent magnetism, magnetic anisotropy, and hysteresis of thiol-capped gold nanoparticles
A1 Crespo del Arco, Patricia
A1 Litran, R.
A1 Rojas, T. C.
A1 Multigner, M.
A1 De la Fuente, J. M.
A1 Sánchez López, J. C.
A1 Garcia, M. A.
A1 Hernando Grande, Antonio
A1 Penadés, S.
A1 Fernández, A.
AB We report on the experimental observation of magnetic hysteresis up to room temperature in thiol-capped Au nanoparticles with 1.4 nm size. The coercive field ranges from 860 Oe at 5 K to 250 Oe at 300 K. It is estimated that the Au atoms exhibit a magnetic moment of mu=0.036mu(B). However, Au nanoparticles with similar size but stabilized by means of a surfactant, i.e., weak interaction between protective molecules and Au surface atoms, are diamagnetic, as bulk Au samples are. The apparent ferromagnetism is consequently associated with 5d localized holes generated through Au-S bonds. These holes give rise to localized magnetic moments that are frozen in due to the combination of the high spin-orbit coupling (1.5 eV) of gold and the symmetry reduction associated with two types of bonding: Au-Au and Au-S.
PB American Physical Society
SN 0031-9007
YR 2004
FD 2004-08-20
LK https://hdl.handle.net/20.500.14352/52018
UL https://hdl.handle.net/20.500.14352/52018
LA eng
NO ©2004 American Physical Society.XAS facilities at BM29 in ESRF and the technical support from O. Mathon are acknowledged. The authors thank J. Llopis and I. Rosa for helping with optical measurements and sample preparation, respectively. Financial support from the Spanish MCyT under Projects No. MAT2002-04246-C05-05 and No. BQU2002-03734 is acknowledged.
NO Spanish MCyT
DS Docta Complutense
RD 3 may 2024