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Nanostructures organized in unordinary spatial arrangements with multiple components such as core–shell configurations endow structures, material properties and functions that differ from the individual bulk components. In this study, we report the synthesis and characterization of bifunctional magnetic–luminescent Fe3O4–CdSe core–shell nanocrystals with core diameter and shell thickness of 10 and 2 nm, respectively, by controlled sequential reactions. The nanocrystals exhibit well-defined superparamagnetic behavior with high susceptibility at RT. Moreover, the fluorescent measurements demonstrate two major kinds of emission peaks, one at 572 nm originating from the bandgap excitons and the other at 680 nm being surface-associated. These core–shell nanocrystals, coupling the optical sensing element with the magnetic actuator in a peculiar nanostructure are thereby prospected for fundamental study and various applications where multifunctionality is required.

Though enzyme-linked immunosorbent assay is widely used in laboratory medicine, it has limitations due to interactions between enzymes and secondary antibodies. Here, we propose a new cardiac assay scheme for detecting troponin I antigens based on La(1– x )Sr x MnO3 ( $x=0.10$ , 0.15, and 0.25) nanoparticles (NPs). These NPs are synthesized via a modified polyol process followed by heat treatment. An increase in $x$ induces changes in crystal structure and increases both Curie temperature and saturation magnetization. The NPs with $x=0.15$ exhibit a Curie temperature close to the human body temperature. The limit of detection is found to be 0.78 ng/mL. We also confirm that LaSrMnO NPs are reusable after heating the assay plate.

Multifunctional high-performance La1−xSrxMnO3@Au core–shell nanoparticles were successfully synthesized by a modified nanoemulsion method with the assistance of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO). X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses confirm the structure and morphology of the nanoparticles. The measurements obtained using ultraviolet-visible light absorbance spectrometry (UV-vis), vibrating sample magnetometry (VSM), and a physical property measurement system (PPMS) demonstrate that the nanoparticles exhibit a surface plasmon resonance (SPR) absorption band around 561 nm from nanostructured Au and a unique magnetic nature at room temperature. Particularly, a sharp, tight phase transition from ferromagnetic to superparamagnetic states is observed in a free-standing La1−xSrxMnO3 nanoparticle system for the first time with a Curie temperature around room temperature. The cytotoxicity of the nanoparticles was studied for safe biomedical applications using an MTT assay. The results show that the La1−xSrxMnO3@Au core–shell nanoparticles with lower cytotoxicity, well-defined magnetic and optical properties are promising for optical, magnetic, and biomedical application.

The polymer-laced Cu-ZnO nanoparticles were successfully synthesized by one-pot non-aqueous nanoemulsion method with the use of PEO-PPO-PEO as the surfactant, C14H29CH(OH)CH2OH as the reducing agent, octyl ether as the solvent, Zn (acac)2 and Cu (acac)2 as precursors. The Morphology and structure of nanoparticles were analyzed by transmission electron microscopy (TEM) and X-ray diffraction (XRD). UV-visible absorption spectroscopy (UV-vis) and photoluminescence spectrometry (PL) were employed to valuate the optical properties of the nanoparticles. The Cu-ZnO nanoparticles with well defined optical properties are promising for optical, catalytic and biomedical applications.

FeAu/ZnO nanoparticles were successfully synthesized by nanoemulsion process with the use of poly (ethylene glycol)-block-poly (propylene glycol)-block-poly (ethylene glycol) as the surfactant. The characterization of the FeAu/ZnO nanoparticles was performed using X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and UV-visible absorption spectroscopy, showing that the polymer-laced nanoparticles reveal high crystallinity, excellent dispersibility and well defined optical performance. The process of solvent dispersion-collection of FeAu/ZnO nanoparticles indicates that the nanoparticles possess good magnetic property for applications.

The polymer-coated AgZnO nanoparticles were synthesized via a one-pot process with the assistance of the triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO). The nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) including the mode of high resolution (HRTEM) and by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible light absorbance spectrometry (UV-vis) and photoluminescence spectrophotometry (PL). It is found that the nanoparticles reveal high crystallinity, good dispersibility, and excellent optical performance both in organic and aqueous solvents. The photocatalytic behavior of the AgZnO nanoparticles was scrutinized using rhodamine B (RhB) as probe molecule. The results show that the degradation efficiency of the AgZnO nanoparticles is higher than that of the ZnO nanoparticles under both UV and sunlight irradiation, 89.5% and 66.9% for the former and 52.7% and 37.5% for the latter after 90 minute exposure, respectively. Moreover, the AgZnO nanoparticles were found to have the photocatalytic efficiency unaltered after 5 cycles of use as tested. Our results demonstrate that the nanostructured AgZnO nanoparticles exhibit enhanced photocatalytic performance and high stability. Consequently, the AgZnO nanoparticles are favorable candidates for potential application as a promising photocatalyst.

Multi-functional CoNiAu nanoparticles were successfully synthesized via nanoemulsion method with the use of PEO-PPO-PEO as the surfactant, C14H29CH(OH)CH2OH as the reducing agent, Ni (acac)2, Co (acac)2 and Au (ac)3 as precursors. The characterization of the CoNiAu nanoparticles was performed using X-ray powder diffraction (XRD), fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM) and UV-vis near IR spectrophotometer (UV-vis). The XRD and TEM analysis confirm the formation and structure of the nanoparticles. The UV-vis and VSM measurements display the optical and magnetic properties of the CoNiAu nanoparticles at the room temperature. The CoNiAu nanoparticles with the well defined optical and magnetic properties are promised for optical, magnetic, catalytic and biomedical applications.

Swelling and shrinkage due to moisture-change is one of the expansive soils characteristics, which is similar to the behavior of most materials under thermal effect. The stress is defined as moisture-change stress and is adopted to analyze swell-shrinkage deformation based on the elasticity mechanics theory. A FEM program is established which is used to calculate the stress caused by moisture-change considering the defect of theoretical calculation. The stress via FEM program can be accordance with the actual characteristics and the moisture-change is more applied extensively.

The expressions of crack spacing and width were deduced from the aspect of force-balance. The concept of maximum spacing and width of crack were put forward accordingly and they were verified and consistent with the site test results. Their relationships with soil parameters were discussed in detail. The new cracks do not appear until the spacing of adjacent cracks is greater than the maximum spacing, and the width of cracks will not be greater than the maximum width. The maximum spacing and width are judgments for describing and represent the final characteristic of cracks due to evaporation.

We report the tunable synthesis and multifunctionalities of Fe 3 O 4 –ZnO hybrid core-shell nanocrystals as prepared through controlled sequential nanoemulsion processes. The characterization shows the orderly variations of the structural, magnetic, photoluminescent and absorption properties of the nanocrystals versus the nanoshell thickness. The nanocrystals reveal structural features unique to the core-shell design and exhibit well-defined superparamagnetic behavior at room temperature. In opposite to the decreasing magnetization, both bandgap and induced surface emissions depend strongly on the increasing nanoshell thickness. Moreover, the FTIR analysis provides the fingerprints of the polymer surfactant, ZnO and Fe 3 O 4 in the same nano-entity and the core-shell nanocrystals could be directly dispersed in both aqueous and organic media for application readiness. Aptly tunable in nanostructures and thus optimized properties, this kind of monosized, high quality, and multifunctional core-shell nanocrystals could be of interest for fundamental studies and potential applications.

Hysteresis effect of contact angle has an important impact on liquid bridges between sphere particles. This effect is not limited to increasing liquid volume of fixed particles. The hysteresis effect of contact angle is expressed by fixed liquid volume while the two sphere particles are in relative movement. The hysteresis effect of contact angle on the liquid bridge is also significant. In this paper, the hysteresis effect of contact angle on capillary forces of liquid bridges is analyzed when the two sphere particles are in relative movement. Results indicate that contact angle hysteresis effects on capillary force are significant.

We report the synthesis method and dimension-dependent magnetic properties of CoFe/Au barcode nanowire arrays. Well-separated multisegment nanowire arrays are synthesized by a pulsed electrodeposition process in a single bath. Samples with four different aspect ratios defined as the CoFe thicknesses to the nanowire diameter are prepared to investigate dimensional effects on the magnetic properties. It is evident except for very low aspect ratio case that each hysteresis loop shows a soft magnetic characteristic with an easy axis parallel to the nanowire axis. Magnetic reversal in most samples is primarily dominated by a transverse domain wall mode.

We report the one-pot synthesis of bifunctional Au–Fe3O4 hybrid core–shell nanoparticles by controlled sequential reactions. The core–shell nanostructure of the resultant nanoparticles is identified by XRD and TEM, which is further substantiated by the changes in the corresponding physical and chemical properties. The nanoparticles exhibit a well-shaped absorption band in the visible region with a remarkable red-shifting to ∼592 nm and show clear superparamagnetic behavior at room temperature along with enhanced susceptibility, demonstrating the integration of the optical and magnetic functions of the respective components in one entity. This kind of bifunctional optical-magnetic core–shell nanoparticles could be of interest in interfacial proximity effects due to the unique spatial nanostructure configuration and have potential applications in various areas.

Swelling and shrinkage due to moisture-change is one of the characteristics of the expansive soil, which is similar to the behavior of most materials under thermal effect. If the deformation is restricted, stress in expansive soil is caused by the swell-shrinking. The stress is defined as “moisture-change stress” and is adopted to analyze swell-shrinkage deformation based on the elasticity mechanics theory. The state when the total stress becomes equal to the soil tensile strength is considered as the cracking criterion as moisture-change increases. Then, the initial cracking mechanism due to evaporation is revealed as follows: Different rates of moisture loss at different depths result in greater shrinkage deformation on the surface while there is smaller shrinkage deformation at the underlayer in expansive soil; cracks will grow when the nonuniform shrinkage deformation increases to a certain degree. A theoretical model is established, which may be used to calculate the stress caused by moisture-change. The depth of initial cracks growing is predicted by the proposed model in expansive soil. A series of laboratory tests are carried out by exposing expansive soil samples with different moisture-changes. The process of crack propagation is investigated by resistivity method. The test results show good consistency with the predicted results by the proposed theoretical model.

Water-dispersible 2 nm FePt ultrasmall nanocrystals coated by a biocompatible triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO) were directly synthesized in a single-step nanoemulsion process. The FTIR investigation proves the PEO-PPO-PEO molecules on the surface of the resulting nanocrystals, which render the nanocrystals hydrophilic for aqueous dispersion without using conventional ligand exchange and offer proper protection of the nanocrystals from oxidation. The structural and morphological analysis reveals both single-crystallinity and high crystallinity of the nanocrystals in the face-centered cubic phase, with an excellent monosize distribution of 1.95 ± 0.18 nm in diameter. Moreover, the polymer-capped nanocrystals possess well-defined magnetic behavior and the aqueous dispersion–collection process of the nanocrystals was demonstrated for application readiness of such ultrasmall nanocrystals in aqueous media.

We study the one-pot facile hydrothermal growth of ultralong silver-carbon (Ag-C) nanocables with Ag nanowires as the cores and carbon as the sheaths through the mediation of H2SO4 and without using an organic surfactant. In the investigation, Ag-C nanostructures were systematically and extensively examined as a function of both temperature and H2SO4 concentration to locate the optimal conditions for preparing ultralong, robust, and uniform Ag-C coaxial nanocables at T = 180 °C and 0.5 M H2SO4. The characterization clearly demonstrated a simple, efficient, and surfactant-free synthesis of Ag-C nanocables. In the hydrothermal process, glycerol acts as both reducing agent and carbon source, while H2SO4 mediates the directional growth of the silver nanowire core and assists the deposition of carbon. Moreover, the nanocables manifest unusual ferromagnetism at room temperature and a plausible mechanism of forming Ag-C nanocables was proposed as a result of the chain-like hydrogen sulfate compounds owing to the H2SO4 mediation.

We report the low-temperature synthesis and characterization of polyvinylpyrrolidone (PVP)-capped FeAu magneto-plasmonic multifunctional nanoparticles by a one-step nanoemulsion process. The Fourier transform infrared spectroscopy study proves the PVP coating on the surface of the resultant FeAu nanoparticles, whereas the structural, magnetic, and optical analysis illustrates the fusion of iron and gold into one single nanostructure showing the nanoparticle shape and a tight size distribution with an average size of 11.3 nm, followed by the growth habit compared to other relevant nanoparticles. Moreover, the PVP-capped FeAu nanoparticles manifest soft ferromagnetic behavior with a small coercivity of ∼40 Oe at room temperature. The corresponding magnetic hysteresis curves were elucidated by modified bi-phase Langevin equations, which were reasonably interpreted with the binary particle size distribution. The nanoparticles reveal a well-defined surface plasmon resonance band at ∼546 nm and a visual demonstration shows the magnetic separability of all nanoparticles for potential magnetic and/or optical manipulation.

Monodisperse, monocrystalline AuFe optical–magnetic multifunctional nanocrystals were prepared by the nanoemulsion method using a copolymer surfactant. The structure and properties of the monocrystalline nanocrystals were analyzed by X-ray diffraction, transmission electron microscopy (TEM, including high-resolution TEM), selected-area electron diffraction, UV-vis spectroscopy, and vibration sampling magnetometry. The characterization shows the outstanding monodispersity and high monocrystallinity of the nanocrystals, which possess both well-defined optical and magnetic properties revealing broadband absorption with the surface plasmon resonance, peaking at ~600 nm, and clear soft ferromagnetic behavior at room temperature. Such long-term stable, monocrystalline AuFe nanocrystals have novel optical and magnetic properties, which may offer exciting opportunities in fundamental studies and tremendous applications.

Monosized core–shell Fe3O4/Au magnetic–optic multifunctional nanoparticles were synthesized by a modified nanoemulsion process. The formation of the core–shell nanostructure was accomplished in the presence of poly(vinylpyrrolidone) (PVP) as the surfactant in two consecutive steps. The comparison FTIR study proves the PVP coating on the surface of the resultant nanoparticles, whereas the morphological analysis illustrates the nanoparticle shape, nanostructuring, size and size distribution and shows the excellent monodispersity

This paper describes the synthesis and magnetic properties of multifunctional Fe3O4-AuPt core-shell nanoparticles. The Fe3O4-AuPt core-shell nanoparticles were synthesized by a one-pot polyol process in two consecutive steps from Fe, Au, and Pt precursors. The structural characterization and property analysis proves the formation of the core-shell nanostructure fusing the multifunctionality in a single entity. The TEM observation shows that the Fe3O4-AuPt core-shell nanoparticles are highly crystalline and uniform in size distribution, with an averaged particle size of ~12.5 nm in diameter, whereas the X-ray diffraction patterns provide further substantiation. The surface plasmon resonance arising from the AuPt nano-shell was revealed by UV-vis spectroscopy, while the magnetic measurements by VSM and PPMS demonstrate the well-defined superparamagnetic and/or soft-ferromagnetic behavior of the Fe3O4-AuPt core-shell nanoparticles.

Multifunctional Au0.5Fe0.5 alloy nanoparticles from a polyol process were investigated, showing the alloy nanostructures with the formation of a new phase and twin microstructures. Giant diamagnetism, on the order of -10- 2 emu g-1 Oe-1 , is observed in the zero-field cooled process of the nanoparticles, which is modeled in terms of the spin-orbital interactions tuned by the modified potential energy as a result of the shrinking dimension, peculiar disordered microstructure, and heterogeneous elemental composition.

Au-doped CoPt nanowires were prepared in anodized aluminum oxide (AAO) nanotemplates by electrodeposition and the doping effects on their microstructure and magnetic properties were investigated. Dependent on the deposition conditions, the CoPtAu nanowires can have the cubic or tetragonal phase. The magnetic measurements indicate that the nanowires demonstrate ferromagnetic behavior, showing the easy axis along the direction of the nanowires and strong enhancement in coercivity and squareness prior to annealing, whereas the optical measurements reveal plasmon resonances characteristic of nanostructured Au.

We have synthesized highly crystalline, monosized Fe3O4(Fe)/Au magnetic-optic multifunctional nanocrystals using a modified polyol process. The formation of the core-shell structure was achieved in two consecutive steps, seeding the Fe3O4(Fe) core followed by coating the gold shell. The characterization demonstrates the core-shell nanostructure and provides particle size and distribution of the nanocrystals. The spectroscopic analysis gives three Fe oxidation states (Fe0, Fe+2 and Fe+3) in the core and the surface plasmon characteristic of the Au nanoshell, while the magnetic measurements show excellent susceptibility of the nanocrystals.

We report the synthesis and characterization of Fe-FeOx core-shell nanowires by thermal conversion of the Fe nanowires from pulse electrodeposition in anodized aluminum oxide (AAO) nanotemplates under various conditions. Well-defined core-shell nanostructure of the Fe-FeOx nanowires was confirmed by TEM and corresponding elemental line scanning and point scanning. The type of the iron oxide in the shell was identified using nano-Raman spectroscopy, which exposes magnetite to be the major constituent. The magnetic measurements demonstrate that the nanowires are robustly soft magnetic, with the magnetization tunable by heat treatment parameters and a weak magnetic easy direction parallel to the nanowire axis.

We report the growth of CoPtAu nanowires by electrodeposition in nanoporous anodic aluminum oxide templates. The composition analysis and elemental mapping reveals that the nanowires are composed of Co, Pt and Au, which are homogenously distributed throughout the nanowires. Under the given deposition conditions, the nanowires were dominated by Pt and Au to form a cubic PtAu phase, with the existence of the CoPt tetragonal phase at higher current densities. The nanowires obtained at 3 and 5 mA/cm2 show ferromagnetic behavior and have an easy-axis parallel to the nanowire axis.

Magnetite nanocrystals of 2–4 nm were synthesized by a chemical coprecipitation method, by which the particle size was controlled by the reaction temperature. The nanocrystals were investigated by XRD, TEM/HRTEM, VSM and SQUID. It is found that the nanocrystals reveal well-defined superparamagnetic behavior before and after annealing, while the observation of the distinct lattices manifest the high crystallinity of the ultrasmall particles.

We synthesized monodisperse CoPt nanoparticles by a modified polyol process, in which Co(acac)3 and Pt(acac)2 were co-reduced by a diol in the presence of PVP surfactants at high temperature (acac = acetylacetonate, PVP = polyvinylpyrrolidone). It is found that the CoPt nanoparticles assume a face-centered cubic phase and possess high crystallinity, with a particle size of 5.3 nm and a tight size distribution. The nanoparticles show superparamagnetism in the as-synthesized state and become ferromagnetic after annealing. The magnetization process of the nanoparticles prior to heat treatment was analyzed by the Langevin equation and their effective magnetic particle size was thus obtained, in close approximation to the results from the XRD and TEM observation.

Fabrication of Co-Pt nanowire arrays with fcc-Co 3 Pt phase was accomplished by DC electrodeposition in anodic aluminum oxide (AAO) nanotemplates. The microstructural and magnetic properties of the nanowires were investigated as a function of the deposition current density (Co concentration). The nanowires possess fcc-Co 3 Pt phases and are ferromagnetic. Their crystallinity and magnetic performance was enhanced after annealing.

We synthesized Fe and Co-based (Fe 48 Co 41 Sι 3 B 8 ) alloy nanopowders by a mechanochemical technique and investigated their structure, magnetic and electromagnetic properties. The nanopowders have a bcc (A2) phase and demonstrate high magnetization with low coercivity. The analysis reveals that their magnetization process may be described by a two-phase model. The microwave measurements performed by the coaxial method over a broad band up to 18 GHz show that the nanocomposites comprising the nanopowders possess high, broadband magnetic permeability, promising applications in electromagnetic shielding and microwave absorption.

Magnetite particles of 2–4 nm were synthesized by an economic, biocompatible chemical coprecipitation route, with their size tuned by the reaction temperature. The microstructure and morphology of the nanoparticles were characterized by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM), whereas the magnetic properties were investigated by vibrating sample magnetometry (VSM) and superconducting quantum interference device (SQUID). It is found that the nanoparticles demonstrate well-defined superparamagnetic behavior as prepared and after annealing. Distinct lattices were observed which manifest the high crystallinity of such ultrasmall particles and the finite-size effect was revealed by analyzing the corresponding microstructure and magnetism.

Structural and microwave properties of Fe-based nanoalloy powders, mechanochemically synthesized with a composition corresponding to Finemet (Fe73.5Si13.5B9Nb3Cu1), were investigated. The nanopowders, dominated by bcc-Fe (Si), consist of nanocrystallites and display high magnetization with low-coercivity. The microwave measurements show that the nanocomposites comprising the nanopowders possess high, broadband magnetic permeability.

Nanowires are a focus of research interests as one-dimensional nanosystems and promise exciting applications in nanotechnology, ranging from nanoelectronic devices to cell separation and magnetic labeling in biomedicine. Avariety of methods have been devised to prepare them from magnetic, semiconductor, inorganic, organic, polymer, metallic, and dielectric materials to provide nanowires with novel optical, electrical, catalytic, and magnetic properties. Multilayered or barcode arrangements of nanowires which incorporate different material components are a special case as a result of their spatial arraying, multiple functionalities, and enhanced properties in comparison to those of their single-component counterparts. For instance, Co–Cu barcode nanowires were explored for their high magnetoresistance compared to that of the well-studied thin films, 17] while the coding of magnetic and optical properties in a single wire was targeted for the separation, detection, and transport of cells. Interested in the transport properties and potential applications of nanowires in nanodevices and biomedicine, we have investigated magnetic nanowires by electrodeposition. For biomedical purposes, however, two issues have to be addressed for the implementation of such nanowires, namely surface modification and biocompatibility. In this respect, the synthesis of iron–gold (Fe–Au) nanowires is appealing not only in terms of magnetic properties but also with respect to biological compatibility. On one hand, iron is favored as it is unique in the field of magnetic materials owing to its high magnetization and physicochemical potentiality. It can be easily converted into oxides, which have been thoroughly studied in the form of magnetic nanoparticles in the biomedical field for their magnetic properties and exceptional biocompatibility. On the other hand, gold is a wellestablished material that displays attractive optical properties, biological compatibility, catalytic activity, and excellent surface effects. Thus, it was anticipated that the integration of these two materials into a one-dimensional barcode arrangement on the nanoscale would produce a new nanostructured material that retains the optical and magnetic properties of the respective components, offering synergistically enhanced performance and functionalities which go beyond those of the individual components. Herein, we report the synthesis and characterization of such a kind of multifunctional magnetic–optical Fe–Au barcode nanostructures, that is, nanowires consisting of alternative Fe magnetic and Au optical segments. The Fe–Au barcode nanowires were constructed using anodic alumina oxide (AAO) templates by pulse electrodeposition thus forming iron and gold segments alternatively in a single bath under desired pulse current densities (e.g. 10 mAcm 2 and 0.5 mAcm ) with regulated pulse durations to control the respective segmental lengths (see Experimental Section). The selection of a current density to electrodeposit Fe or Au was based on the evaluation of the composition versus current density profile (Figure 1a), which was acquired from the analysis of the samples each obtained at a given constant current density, by inductively coupled

Bi-phase dispersible core-shell FeAu@ZnO magneto-opto-fluorescent nanoparticles were synthesized by a modified nanoemulsion process using poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO) as the surfactant. The morphology and crystal structure of the nanoparticles were studied by TEM/HRTEM and XRD. The nanoparticles manifest soft ferromagnetic and/or near superparamagnetic behavior with a small coercivity of ~19 Oe at room temperature. The corresponding magnetic hysteresis curves were elucidated by the modified Langevin equation. The FTIR study confirms the PEO-PPO-PEO molecules on the surface of the nanoparticles. The UV-vis and PL results reveal the well-behaved absorption bands including surface plasmon resonance and multiple visible fingerprint photoluminescent emissions of the nanoparticles dispersed in both hydrophilic and hydrophobic solvents. Moreover, the processes of solvent dispersion-collection of the nanoparticles were demonstrated for application readiness of such core-shell nanostructures.

Cobalt nanowires were fabricated by DC electrodeposition onto anodic aluminium oxide (AAO) templates. The effects of AAO pore diameter, current density, pH, annealing and deposition under external magnetic fields on the structure and magnetic properties of the nanowire arrays were studied. It is found that the smaller pore size produces high crystallinity, resulting in improved magnetic performance at low current density. The pH can transform fcc-Co phase to hcp-Co phase, with the easy axis along the nanowire axis switched over to the perpendicular direction. Annealing demonstrates excellent thermal stability of the magnetic nanowire arrays at high temperature. The application of external magnetic field during deposition influences the growth habit of the nanowires, leading to the change in the magnetic properties.

Soft-magnetic FeCo alloy nanoparticles with diameters less than 100 nm are prepared by ball milling. X-ray photoemission spectroscopy (XPS) and X-ray magnetic circular dichroism (XMCD) are used to characterize these particles. While the XPS spectrum from the as-prepared sample clearly shows Co photoemission peaks, no sign of Fe is observed in the same spectrum. However, Fe photoemission peaks appear after 1 h of Ar ion sputtering. A quantitative analysis of the XPS spectra shows an increase of Fe concentration versus sputtering time until the Fe:Co ratio of the bulk alloy is reached. In addition, the narrow scan Fe and Co 2p XPS spectra show that Co is more oxidized than Fe. All these measurements indicate that the nanoparticles have a Co shell and an Fe-rich core. They further demonstrate the usefulness of XPS combined with depth-profiling via sputtering to obtain element- and chemically-sensitive structural information on nanoparticles. XMCD as an element-specific magnetic analysis tool further reveals that Fe and Co are ferromagnetically coupled in these particles. The information obtained is useful for establishing a structure–property relation for the studied material that is expected to have applications as a soft magnetic material at high temperatures.

Bi-phase dispersible Cu-ZnO hybrid nanoparticles were synthesized by one-pot non-aqueous nanoemulsion with the use of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO) as the surfactant. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) show high crystallinity of the Cu-ZnO hybrid nanoparticles and an average particle size of ~19.4 nm. The ultraviolet-visible light absorbance spectrometry (UV-vis) and photoluminescence spectrophotometry (PL) demonstrate well dispersibility and excellent optical performance of Cu-ZnO hybrid nanoparticles both in organic and aqueous solvent. The X-ray photoelectron spectroscopy (XPS) confirms Cu(1+) and Cu(2+) in ZnO. The observation using Sudan red (III) as probe molecule reveals that the Cu-ZnO hybrid nanoparticles possess enhanced photocatalytic activity and stability which are promising for potential applications in photocatalysis.

Bi-phase dispersible ZnO-Au hybrid nanoparticles were synthesized via one-pot non-aqueous nanoemulsion using the triblock copolymer poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) as the surfactant. The characterization shows that the polymer-laced ZnO-Au nanoparticles are monosized and of high crystallinity and demonstrate excellent dispersibility and optical performance in both organic and aqueous medium, revealing the effects of quantum confinement and medium. The findings show two well-behaved absorption bands locating at approximately 360 nm from ZnO and between 520 and 550 nm from the surface plasmon resonance of the nanosized Au and multiple visible fingerprint photoluminescent emissions. Consequently, the wide optical absorbance and fluorescent activity in different solvents could be promising for biosensing, photocatalysis, photodegradation, and optoelectronic devices.

We report the morphology, texture, mechanical properties of Ni films with nanosized grains prepared by electrodeposition as a function of current density. With an increase in current density, the morphology of the nanostructured films was greatly affected and the textures changed from face-centered cubic (1 1 1)- to (2 0 0)-orientation. Consequently, the textural and microstructural alteration exerted strong influence on the hardness of the films, leading to decrease in the hardness (in particular, the inverse Hall–Petch relation) as current density increased, attributed to the distribution of colonies of grain agglomerate and the variation of directional tensile strength.

We have used a simple and direct method to successfully prepare Ag2Se thin films by pulse electrodeposition from a single aqueous solution of Ag and Se ions. The composition analysis confirms the stoichiometry and the morphological characterization shows that the thin films are dense and smooth. The films have the orthorhombic structure of regular Ag2Se materials at room temperature, while the electrical measurements reveal an interesting electrical behavior, similar to that of the Ag2Se nanowire arrays. The Ag2Se thin films were successfully deposited into polymer templates to form well-defined Ag2Se nanostructure, which provides a possibility to apply the method to high density, non-volatile memories based on phase change materials.

Polyvinylpyrrolidone (PVP)-coated sub-5 nm monosize Fe 3 O 4 nanoparticles were synthesized by reduction of Fe(III) acetylacetonate in the presence of PVP polymer as surfactant in one-pot polyol process. Their microstructure and magnetic properties were characterized by XRD, TEM/HRTEM and VSM. It is found that the nanoparticles have high crystallinity with distinct lattices and the magnetic measurements reveal their well-defined superparamagnetic behavior at room temperature. Such Fe 3 O 4 nanoparticles with tailorable size and tunable magnetic properties are promising for biomedical applications.

We have studied the effect of an external magnetic field applied during electrodeposition of Co/Cu barcode nanowires in anodic aluminum oxide nanotemplates. The magnetic properties of the barcode nanowires were greatly enhanced for 50 nm pore diameter regardless of segment aspect ratio, but field deposition has little effect on the 200 nm nanowires. The magnetic improvement is correlated with a structural change, attributed to field modification of the growth habit of the barcode nanowires. A mechanism of growth subject to geometric confinement is proposed.

CoCu thin films were fabricated on a nanocrystalline substrate by DC electrodeposition. It is found that the composition, structure and magnetic properties of the thin films exhibit a strong dependence on the current density and pH values of the bath electrolyte. The effect of annealing as well as the structure–property relation was investigated.

We report the synthesis and characterization of ferrite nanocrystals which exhibit high crystallinity and narrow size distributions. The three types of samples including Zn ferrite, Mn ferrite, and Mn-Zn ferrite were prepared via a non-aqueous nanoemulsion method. The structural, chemical, and magnetic properties of the nanocrystals are analyzed by transmission electron microscopy, X-ray diffraction, X-ray fluorescence, and physical property measurement system. The characterization indicates that the three types of ferrite nanocrystals were successfully produced, which show well-behaved magnetic properties, ferrimagnetism at 5 K and superparamagnetism at 300 K, respectively. In addition, the magnetization value of the ferrites increases with the increasing concentration of Mn.

Complex permittivity spectra of the multiwalled carbon nanotube (MWNT)-epoxy composites with mass concentrations up to 25.9% were measured from 10 MHz to 20 GHz. The composites exhibit high real and imaginary relative permittivities over broad bandwidth, showing strong dependence on the MWNT loading. It is observed that distinct resonance takes place at ∼1.5 GHz, with the corresponding resonant frequency shifts downward as the MWNT concentration increases. The origin of the dielectric properties is explained in terms of the dielectric relaxation/resonance and electrical conduction behavior of the nanotube composites, substantiated by the agreement between simulation and experimental data.

We explored the feasibility of magnetite (Fe(3)O(4))-gold (Au) core-shell nanocrystals as a useful vehicle for biomedical application such as cell separation. Streptavidin-fluorescein isothiocyanate (STA-FITC) was conjugated to the surface of the Fe(3)O(4)-Au core-shell nanocrystals using a carbodimide activation protocol. These nanocrystals were further tested for their ability to bind CD4+ T lymphocytes, bound to biotin-labeled anti-CD4 mAbs, isolated from the spleen of C57BL/6 mice. Our data show that the Fe(3)O(4)-Au nanocrystals successfully pulled down CD4+ T lymphocytes from the whole splenocytes with high specificity. Therefore, our nanocrystals provide an efficient tool for the cell separation process and further present the dramatic potential to be applied to other areas of biomedical application including diagnosis, monitoring, and treatment of human diseases.

The authors synthesized ultra-small magnetite (Fe3O4) nanoparticles using aqueous coprecipitation. The crystal structure of the samples was analyzed by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The magnetic properties of the magnetite nanocrystals were investigated using a SQUID magnetometer.

We report the efficiency of genomic DNA extraction as a function of particle size and quantity. For DNA extraction, we synthesized magnetic nanoclusters of various sizes and coated the surface of these magnetic nanoclusters with meso-2,3-dimercaptosuccinic acid. We showed that the nanoclusters had a tight particle size distribution and high crystallinity. Furthermore, we observed that the three types of magnetic nanoclusters studied exhibited ferrimagnetic behavior and that larger nanoclusters showed larger saturation magnetization values. The resultant efficiency of DNA extraction is inversely proportional to particle size in the range of nanoclusters tested, due to the fact that the surface-to-volume ratio decreases as particle size increases.

We report a simple approach to synthesize ZnO–Ag composite nanocrystals with different ZnO/Ag ratios via a nanoemulsion process. The morphology and structure of the nanocrystals are investigated by X-ray diffraction and transmission electron microscopy, showing the high crystallinity of the nanocrystals with narrow size distributions. The corresponding optical and magnetic properties are analyzed with photoluminescence spectroscopy, ultraviolet–visible spectrometry and physical property measurement system in detail. The ensuing magnetism is interpreted in terms of nanosizing and other effects. Such ZnO–Ag nanocrystals may be further explored for biomedical applications and spintronic devices with interesting optical and magnetic properties.

Nanobarcodes consisting of multicomponents and multisegments have gained attention lately because they can offer multiple functionalities. Here, we report the structure, composition, and magnetic properties of CoFe/Au nanobarcodes fabricated by a pulsed electrodeposition method in one solution bath. The nanobarcodes with three different compositions in magnetic segments including Co68Fe32 (Co-rich), Co50Fe50 (equiatomic), and Co35Fe65 (Fe-rich) exhibit different magnetic characteristics as a result of compositional variation. The highest saturation magnetization value of 1739 emu/cm3 was observed in the Fe-rich case.