Junbao Wang

Seed‐Induced Growth of Flower‐Like Au–Ni–ZnO Metal–Semiconductor Hybrid Nanocrystals for Photocatalytic Applications

The combination of metal and semiconductor components in nanoscale to form a hybrid nanocrystal provides an important approach for achieving advanced functional materials with special optical, magnetic and photocatalytic functionalities. Here, a facile solution method is reported for the synthesis of Au-Ni-ZnO metal-semiconductor hybrid nanocrystals with a flower-like morphology and multifunctional properties. This synthetic strategy uses noble and magnetic metal Au@Ni nanocrystal seeds formed in situ to induce the heteroepitaxial growth of semiconducting ZnO nanopyramids onto the surface of metal cores. Evidence of epitaxial growth of ZnO{0001} facets on Ni {111} facets is observed on the heterojunction, even though there is a large lattice mismatch between the semiconducting and magnetic components. Adjustment of the amount of Au and Ni precursors can control the size and composition of the metal core, and consequently modify the surface plasmon resonance (SPR) and magnetic properties. Room-temperature superparamagnetic properties can be achieved by tuning the size of Ni core. The as-prepared Au-Ni-ZnO nanocrystals are strongly photocatalytic and can be separated and re-cycled by virtue of their magnetic properties. The simultaneous combination of plasmonic, semiconducting and magnetic components within a single hybrid nanocrystal furnishes it multifunctionalities that may find wide potential applications.

Interfacial-scattering?induced enhancement of the anomalous Hall effect in uniform Fe nanocluster-assembled films

We report on the cluster size dependence of the anomalous Hall effect (AHE) in uniform Fe nanocluster-assembled films prepared by the plasma-gas-condensation method. In particular, a large enhancement of the AHE is observed at , which is almost four orders of magnitude larger than bulk Fe. The saturated anomalous Hall resistivity shows a sharp decrease as d increases from 4.3 to 10.1 nm and a slight decrease with further increasing d to 16.1 nm. Moreover, in double-logarithmic scales, decreases with the increase of longitudinal resistivity , obeying a new scaling relation of , which originates from the interfacial scattering to the AHE and longitudinal resistivity.

Enhancement of inductance and quality factor in GHz range of solenoid inductor by integrating [Fe 80 Ni 20 -O/SiO 2 ] n magnetic multilayer films

With the rapid development of science and technology, the demands for miniaturization, integration and high frequency of the electromagnetic devices were steadily increased. The integrated inductor is an important passive component for RF devices such as power transformers, amplifiers and oscillators. However, the performance of on-chip integrated inductors was poor when operating in GHz band. It is well known that, the integration of a magnetic material as magnetic core can effectively improve the performance of inductors [1]. The normal magnetic materials have very lower resonance frequencies (fr), which cant meet the demand of the high frequency inductance components. But if the magnetic films have in-plane uniaxial magnetic anisotropy, the fr can be exceeded 1 GHz [2]. According to the theoretical calculation results, when serving as magnetic core in solenoid inductor, the magnetic films need to hold excellent soft magnetic performance even for the thickness of the film larger than 200 nm. For high frequency soft magnetic monolayer films and granular films, the high frequency magnetic performance are degenerated drastically because of strong inner stress and large grain size when the film thickness increases to a few hundreds of nanometers. Based on our previous study, the multilayer technology can help to maintain good high frequency soft magnetic properties even though the film is very thick [3]. Therefore, the [Fe80Ni20-O/SiO2]n multilayer magnetic film was selected as magnetic core to fabricate the on-chip integrated solenoid inductor and improve the performance of the inductor.

Adjusting the magnetic properties of Ni 0.5 Zn 0.5 Fe 2 O 4 thin film for high frequency applications by introducing Fe 65 Co 35 alloy nanoclusters

In this work, a new preparation method was developed to in situ assembly of nanocluster-matrix binary magnetic nanocomposite films, in which the Fe₆₅Co₃₅ alloy nanoclusters prepared by plasma-gas-condensation nanocluster beam deposition method were encapsulated into Ni_0.5Zn_0.5Fe₂O₄ thin films fabricated via radio frequency magnetron sputtering. The structure and magnetic properties of the composite films have been investigated systematically by using TEM, SEM, XRD, XPS, and VSM .