The PEG-coated ferrite nanoparticles CoMnZnFeO (X1), CoMnZnFeO (X2), and CoMnZnFeO (X3) were synthesized by the coprecipitation method. The nanoparticles were characterized by XRD, Raman, VSM, XPS, and TEM. The magnetic hyperthermia efficiency (MH) was determined for PEG-coated nanoparticles using an alternating magnetic field (AMF).
View Article and Find Full Text PDFMetal halide perovskites show remarkable optical properties and useful applications in optoelectronic devices. However, the instability of three-dimensional (3D) metal halide perovskites limits their applications, leading to the emergence of more stable two-dimensional (2D) metal halide perovskites. Herein, we present a facile synthesis of the 2D hybrid metal halide perovskite (EDA)(MA)PbBr (EDA: ethylene diammonium, MA: methylammonium), where = 1-6, and MAPbBr perovskite layers using an anti-solvent co-precipitation technique.
View Article and Find Full Text PDFCobalt oxide, nickel oxide and cobalt/nickel binary oxides were synthesised by electrodeposition. To fine tune composition of CoNi alloys, growth parameters including voltage, electrolyte pH/concentration and deposition time were varied. These produced nanomaterials were used as binder free electrodes in supercapacitor cells and tested using three electrode setup in 2 MKOH aqueous electrolyte.
View Article and Find Full Text PDFAiming to obtain hybrid magneto-plasmonic nanostructures, we have developed multisegmented and core/shell structured Fe-Au nanorods using template assisted electrochemical deposition. A facile method of tuning the growth pattern of multisegmented nanorods into core/shell structured is demonstrated. With a precise control of current density and deposition time, a brick-stacked wire like growth led to the formation of hollow nanotubes that could be further tuned to multilayered hollow nanotubes and core/shell structured nanorods.
View Article and Find Full Text PDFMagnetically soft-soft MnFeO-FeO core-shell nanoparticles were synthesized through a seed-mediated method using the organometallic decomposition of metal acetyl acetonates. Two sets of core-shell nanoparticles (S1 and S2) of similar core sizes of 5.0 nm and different shell thicknesses (4.
View Article and Find Full Text PDFCobalt nanowires have been synthesized by electrochemical deposition using track-etched anodized aluminum oxide (AAO) templates. Nanowires with varying spacing-to-diameter ratios were prepared, and their magnetic properties were investigated. It is found that the nanowires' easy magnetization direction switches from parallel to perpendicular to the nanowire growth direction when the nanowire's spacing-to-diameter ratio is reduced below 0.
View Article and Find Full Text PDFFe-based colloids with a core/shell structure consisting of metallic iron and iron oxide were synthesized by a facile hot injection reaction of iron pentacarbonyl in a multi-surfactant mixture. The size of the colloidal particles was affected by the reaction temperature and the results demonstrated that their stability against complete oxidation related to their size. The crystal structure and the morphology were identified by powder X-ray diffraction and transmission electron microscopy, while the magnetic properties were studied at room temperature with a vibrating sample magnetometer.
View Article and Find Full Text PDFIn this paper, we report a one-pot chemical synthesis technique for the preparation of iron and iron-carbide nanoparticles. Mössbauer spectroscopy, X-ray diffraction and magnetometry were used as the main tools to identify the different phases of Fe-C present. The influence of experimental parameters on the structural and compositional properties of nanoparticles was investigated in detail.
View Article and Find Full Text PDFPurpose: To evaluate the thrombus maturity noninvasively providing the promise of much earlier and more accurate diagnosis of diseases ranging from stroke to myocardial infarction to deep vein thrombosis.
Methods: Magnetic spectroscopy of nanoparticle Brownian rotation (MSB), a form of magnetic particle spectroscopy sensitive to Brownian rotation of magnetic nanoparticles, was used for the detection and characterization of blood clots. The nanoparticles' relaxation time was quantified by scaling the MSB spectra in frequency to match the spectra from nanoparticles in a reference state.
A series of techniques have been developed to use magnetic nanoparticles as biosensors to characterize their local microenvironment. Two approaches have been used to obtain quantitative information: model based approaches and scaling based approaches. We have favored scaling based approaches, because approximations made in models can lead to limitations in the accuracy.
View Article and Find Full Text PDFDeep vein thrombosis, the development of blood clots in the peripheral veins, is a very serious, life threatening condition that is prevalent in the elderly. To deliver proper treatment that enhances the survival rate, it is very important to detect thrombi early and at the point of care. We explored the ability of magnetic particle spectroscopy (MSB) to detect thrombus via specific binding of aptamer functionalized magnetic nanoparticles with the blood clot.
View Article and Find Full Text PDFInt J Magn Part Imaging
June 2017
The extremely high sensitivity that has been suggested for magnetic particle imaging has its roots in the unique signal produced by the nanoparticles at the frequencies of the harmonics of the drive field. That sensitivity should be translatable to other methods that utilize magnetic nanoparticle probes, specifically towards magnetic nanoparticle spectroscopy that is used to measure molecular biomarker concentrations for an " ELISA" assay approach. In this paper, we translate the predicted sensitivity of magnetic particle imaging into a projected sensitivity limit for ELISA.
View Article and Find Full Text PDFThe exploration of exchange bias (EB) on the nanoscale provides a novel approach to improving the anisotropic properties of magnetic nanoparticles for prospective applications in nanospintronics and nanomedicine. However, the physical origin of EB is not fully understood. Recent advances in chemical synthesis provide a unique opportunity to explore EB in a variety of iron oxide-based nanostructures ranging from core/shell to hollow and hybrid composite nanoparticles.
View Article and Find Full Text PDFDisorder among surface spins is a dominant factor in the magnetic response of magnetic nanoparticle systems. In this work, we examine time-dependent magnetization in high-quality, monodisperse hollow maghemite nanoparticles (NPs) with a 14.8 ± 0.
View Article and Find Full Text PDFA new approach to develop highly ordered magnetite (Fe3O4) nanoparticle-patterned nanohole arrays with desirable magnetic properties for a variety of technological applications is presented. In this work, the sub-100 nm nanohole arrays are successfully fabricated from a pre-ceramic polymer mold using spin-on nanoprinting (SNAP). These nanoholes a then filled with monodispersed, spherical Fe3O4 nanoparticles of about 10 nm diameter using a novel magnetic drag and drop procedure.
View Article and Find Full Text PDFThe development of positive magnetic entropy change in the case of ferromagnetic (FM) nanostructures is a rare occurrence. We observe positive magnetic entropy change in core/shell (Fe/γ-Fe2O3) and hollow (γ-Fe2O3) nanoparticles and its origin is attributed to a disordered state in the nanoparticles due to the random distribution of anisotropy axes which inhibits any long range FM ordering. The effect of the energy barrier distribution on the magnetic entropy change and its impact on the universal behavior based on rescaled entropy change curves for core/shell and hollow nanostructures is discussed.
View Article and Find Full Text PDFWe report a novel synthesis approach for the growth of core/shell FeO/Fe3O4 nanoparticles with controlled shape and size. FeO particles were partially oxidized to form core/shell FeO/Fe3O4 structures, as evidenced from transmission electron microscopy, X-ray diffraction, and magnetometry analysis. We find that the molar ratios and concentrations of surfactants are the key parameters in controlling the particle size.
View Article and Find Full Text PDFIn this work, we report a detailed study of the formation of hollow nanostructures in iron oxides. Core/shell Fe/Fe-oxide nanoparticles were synthesized by thermal decomposition of Fe(CO)(5) at high temperature. It was found that 8 nm is the critical size above which the particles have a core/shell morphology, whereas below this size the particles exhibit a hollow morphology.
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