Magnetic order of Au nanoparticle with clean surface
Source abstract
Abstract
Abstract Au nanoparticles, which are kept in vacuum after the preparation by gas evaporation method, show ferromagnetism even in 1.7 nm in diameter. The intrinsic magnetism is examined by detecting the disappearance of spontaneous magnetization in Au bulk prepared by heating the nanoparticles without exposure to the air. The temperature dependence of spontaneous magnetization is not monotonic and the increase in magnetization is observed after Au nanoparticles are exposed to the air. The magnetic behavior can be interpreted by the ferrimagnetic-like core–shell structure with shell thickness of 0.16±0.01 nm and magnetic moment of (1.5±0.1)×10 −2 μ B /Au atom, respectively.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: nanoparticles nucleation surface interactions · Theoretical and Computational Physics · Magnetic properties of thin films
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (20)
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15. Impurities of 9ppm Fe and a very small amount of Ni and Co (< 5ppm) were detected by inductively coupled plasma atomic emission spectroscopy, and the magnetic contribution from the impurities is less than 2% of total magnetization.
16. Recently, Au nanoparticles, prepared by the same sample preparation method as that in this study, were investigated by means of XMCD technique in magnetic fields up to 10T. The XMCD signals were observed at the Au L2,3 edges, but they are mainly attributed to the paramagnetic origin in high magnetic field at 5K because of the linear magnetic field dependence of XMCD intensity similar to that of the Au foil (bulk Au) (The paramagnetic contribution in Au bulk was verified by XMCD in Phys. Rev. Lett. 108, 047201(2012). On the other hand, XMCD intensity of nanoparticles, obtained at 300K, showed the nonlinear field dependence similar to the ferromagnetic magnetization curve. This indicates that the intrinsic spontaneous magnetization certainly exists in Au nanoparticles and it is almost hidden in the paramagnetic contribution in high magnetic field at low temperatures.
17. The spontaneous magnetizations and the margins of error were estimated by the linear least squares fitting of the high magnetic field data in the magnetization curves obtained at various temperatures. The margin of error for sample A is larger than that of sample B This is mainly because both the amount and magnetization of sample A are smaller as compared with sample B where the sample A of 0.99 mg and sample B of 1.44mg were used for magnetic measurements. The increase in error, observed in sample A at temperatures 50–100K, is due to the condition of magnetometer and it is not intrinsic to the sample.
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