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Shi Y.G.,Nanjing University of Aeronautics and Astronautics | Shi Y.G.,Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education | Chen Z.Y.,Nanjing University of Aeronautics and Astronautics | Chen Z.Y.,Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education | And 8 more authors.
AIP Advances | Year: 2016

The structure, magnetic properties and magnetostriction of high-pressure synthesized Pr1-xDyx(Fe0.8Co0.2)1.93 compounds were investigated. These compounds, which could not be readily synthesized under ambient pressure, exhibit single cubic Laves phase owing to the effects of high-pressure annealing. The Curie temperature increases with increasing x, indicating that 3d-4f coupling becomes stronger with the increase of Dy concentration. The saturation magnetization decreases with increasing x, which can be ascribed to the competition of sublattice magnetization. The easy magnetization direction of the compound lies along < 111 > with x ≤ 0.05 while lies along < 100 > when x ≥ 0.10. Meanwhile, the low-field magnetostriction λ∥ - λ⊥ of the compound system peaks at x = 0.05 and then decreases with increasing x, which reveals that the composition anisotropy compensation between Pr3+ and Dy3+ might be realized in Pr1-xDyx(Fe0.8Co0.2)1.93 system. Pr0.95Dy0.05(Fe0.8Co0.2)1.93 compound combines a large low-field magnetostriction (648 ppm at 3 kOe) and the merits of low-cost raw materials, which may make it a potential material for magnetostrictive application. © 2016 Author(s).


Liu J.,Nanjing University of Aeronautics and Astronautics | Kan C.,Nanjing University of Aeronautics and Astronautics | Kan C.,Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education | Li Y.,Nanjing University of Aeronautics and Astronautics | And 4 more authors.
Plasmonics | Year: 2014

Well-defined assemblies of Au nanorods (NRs) exhibit outstanding optical and electric properties, including surface plasmon resonance (SPR) of an individual nanorod and the coupling SPR among the assemblies. We present a direct approach for end-to-end (E-E) and side-by-side (S-S) assembly of Au NRs using poly (ethylene glycol) dithiol (HS-PEG-SH) and cysteine (Cys), respectively. The coupling SPR properties between the neighboring Au NRs are studied through experimental measurements and finite-different time-domain (FDTD) simulations. The simulated SPR tunability over the assembly agree with that of the experimental results, and both of the longitudinal SPR shifts for E-E and S-S assemblies are well fitted with the exponential function. The present assembled method provides a way for directing anisotropic nanostructures into well-defined orientations, and will be potentially useful in optoelectronics and biomedical engineering. © 2014 Springer Science+Business Media New York.


Kan C.,Nanjing University of Aeronautics and Astronautics | Kan C.,Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education | Li Y.,Nanjing University of Aeronautics and Astronautics | Liu J.,Nanjing University of Aeronautics and Astronautics | And 2 more authors.
Transactions of Nanjing University of Aeronautics and Astronautics | Year: 2014

The surface plasmon resonance (SPR) of gold (Au) nanorod can be tuned in a large visible-near infrared (Vis-NIR) region by changing the aspect ratio of nanorod. Compared with the SPR of isolated Au nanorod, assembly of Au nanorods exhibits strong coupling effect in the nanogap and wealthy changes in the optical spectra. The SPR coupling effects and localized electronic fields for end-to-end (E-E) and side-by-side (S-S) assembled Au nanorods dimers are studied through finite-difference time-domain (FDTD) simulation. With decreasing the gap spacing, the longitudinal SPR (SPRL) red-shifts for the E-E orients Au nanorods dimer and blue-shifts for S-S orientes Au nanorods dimer. The transverse SPR (SPRT) has slight red-shifting for S-S assembly and no shifting for the E-E assembly. Moreover, a new coupling SPR appears for the E-E assembly in a long wavelength in the NIR region, blue-shifting and enhancing with decreasing the gap spacing. Based on the spring oscillator model and the polarization of nanoparticles with incident electric field, the SPR shifting and the appearance of new coupling SPR of assembled Au nanorods are proposed.


Liu J.,Nanjing University of Aeronautics and Astronautics | Kan C.,Nanjing University of Aeronautics and Astronautics | Kan C.,Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education | Cong B.,Nanjing University of Aeronautics and Astronautics | And 5 more authors.
Plasmonics | Year: 2014

Au nanorod (Au NR) is one of the most studied colloidal nanostructures for its tunable longitudinal surface plasmon resonance (SPRL) property in the near infrared region. And surface coating Au NRs into core-shell nanostructures is particularly important for further investigation and possible applications. In this paper, Au NRs colloids were synthesized using an improved seed method. Then as-prepared Au NRs were coated with SiO2 to form a core-shell nanostructure (Au@SiO2) with different shell thickness. And the influence of SiO2 shell on the SPRL of Au NRs was investigated based on the experimental results and FDTD simulations. Under the 808 nm laser irradiating, the stability of Au@SiO2 was studied. Compared with Au NRs, the Au@SiO2 is stable with increasing laser power (up to 8 W), whereas Au NRs undergo a shape deformation from rod to spherical nanoparticle when the laser power is 5 W. The high stability and tunable optical properties of core-shell structured Au@SiO2, along with advantages of SiO2, show that Au@SiO2 composites are promising in designing plasmonic photothermal properties or further applications in nanomedicine. © 2014, Springer Science+Business Media New York.


Lu B.,Nanjing University of Aeronautics and Astronautics | Kan C.,Nanjing University of Aeronautics and Astronautics | Kan C.,Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education | Ke S.,Nanjing University of Aeronautics and Astronautics | And 5 more authors.
Plasmonics | Year: 2016

Bimetallic nanoparticles have attracted increasing interest because of their unique optical, electronic, magnetic, and catalytic properties which are different from that of their individual constituent metals. In this paper, we report a facile route to the synthesis of Pd-covered and Pd-tipped gold nanorods (AuNRs). And finite-different time-domain (FDTD) is also applied to simulate the longitudinal surface plasmon resonance (SPRL) characteristics for two different layered growth modes. The simulated absorption spectra agree with the experimental results. For the Pd-covered AuNRs, it is found that the SPRL shows a red-shift with shell thickness less than 2 nm. And then, the SPRL blue-shifts and gradually approaches to the absorption peak of Pd nanocuboids with increasing Pd shell thickness. While the SPRL of Pd-tipped AuNRs red-shifts with increasing Pd tip-particle size, it is revealed that the bimetallic Au@Pd NRs have higher refractive index sensitivities than that of AuNR cores. The tunable SPRL and higher refractive index sensitivities of bimetallic Au@Pd NRs may lead to great potential applications in many Pd-catalyzed reactions and provide an important reference of Pd nanostructures for SPR-based sensing. © 2016 Springer Science+Business Media New York

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