Search NASA⌕ Search

SEARCH · Search NASA

Results for “SUPERPARAMAGNETISM”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Influence of carbon chain length on the synthesis and yield of fatty amine-coated iron-platinum nanoparticles

Iron oxide nanoparticles are among the most widely used and characterized magnetic nanoparticles. However, metal alloys such as superparamagnetic iron-platinum particles (SIPPs), which have better magnetic properties, are receiving increased attention. Scalable techniques to routinely synthesize SIPPs in bulk need further study. Here, we focus on the role played by the fatty amine ligand in the formation of the bimetallic FePt nanocrystal. More specifically, we compare the effect of varying lengths of fatty amine ligands on the shape, structure, uniformity, composition, and magnetic properties of the SIPPs. We synthesized SIPPs by employing a ‘green’ thermal decomposition reaction using fatty amine ligands containing 12 to 18 carbons in length. Greater fatty amine chain length increased the polydispersity, particle concentration, iron concentration, and the stability of the SIPPs. Additionally, longer reflux times increased the diameter of the particles, but decreased the iron concentration, suggesting that shorter reaction times are preferable. Fourier transform infrared spectroscopy of the SIPPs indicates that the ligands are successfully bound to the FePt cores through the amine group. Superconducting quantum interference device magnetometry measurements suggest that all of the SIPPs were superparamagnetic at room temperature and that SIPPs synthesized using tetradecylamine had the highest saturation magnetization. Our findings indicate that the octadecylamine ligand, which is currently used for the routine synthesis of SIPPs, may not be optimal. Overall, we found that using tetradecylamine and a 30-min reflux reaction resulted in optimal particles with the highest degree of monodispersity, iron content, stability, and saturation magnetization.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Active Experiments in Space: The Future

Planned active space experiments and ideas for future active space experiments are reviewed. Three active experiments being readied are DSX (Demonstration and Space eXperiments), SMART (Space Measurement of Rocket-released Turbulence), and BeamPIE (Beam Plasma Interaction Experiment). Ideas for future experiments include relativistic-electron-beam experiments for magnetic-field-line tracing, relativistic-electron-beam experiments to probe the middle atmosphere, plasma-wave launching using superparamagnetic-nanoparticle amplification of magnetic fields, the heavy-ion mass loading of collisionless magnetic-field-line reconnection, the use of electrostatically charged tethers to pitch-angle scatter radiation-belt particles, cold plasma releases to modify magnetospheric plasma physics, and neutral-gas releases to enhance neutral-particle imaging of the magnetosphere. Technologies that are being developed to enable future space active experiments are reviewed: this includes the development of compact relativistic accelerators, superparamagnetic particle amplified antennae, CubeSats, and a new understanding of how to control dynamic spacecraft charging. New capabilities to use laboratory facilities to design space active experiments as well as new computer-simulation capabilities to design and understand space active experiments are reviewed.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1973

Amorphous magnetism in f.c.c. Vicalloy II

The results of magnetization and Mossbauer experiments are described which give evidence for superparamagnetism in the quenched face-centered-cubic (gamma) phase of the ternary system Fe .34, C .52, V .14 (Vicalloy II). Magnetometer data are given which clearly show that splat-cooled Vicalloy II does not exhibit long-range magnetic order. These data together with the Mossbauer data indicate that short-range magnetic ordering occurs which is temperature-dependent with coalescence of magnetic clusters over a limited temperature range. The model presented reasonably accounts for the observed effects and indicates that this ternary system is superparamagnetic down to 4.2 K.

Cusick, J. P.↗
NASA NTRS1975

Petrographic and ferromagnetic resonance studies of experimentally shocked regolith analogs

Studies of porous aggregates of a regolith analog system composed of a 50:50-wt% mixture of labradorite and bronzite shocked at approximately 100-kbar intervals up to approximately 500 kbar are described, and characteristics of the well-indurated 'rock' formed at all pressures are reported. Ferromagnetic resonance studies of diopside and bronzite that were shocked at approximately 500 kbar are also reported. The formation of metallic particles in the superparamagnetic and single-domain size range as well as the metal fractionation are characterized, and the results suggest that the superparamagnetic and single-domain metallic particles in lunar soils may be produced by shock-induced dissemination of meteoritic and indigenous metal.

Gibbons, R. V.↗
NASA NTRS1990

Origins of Marslike spectral and magnetic properties of a Hawaiian palagonitic soil

Results are presented on spectral, Moessbauer, static magnetic, petrographic, and compositional data for a Hawaiian palagonitic soil from Mauna Kea (HWMK1). It was found that reflectivity spectra of size separates smaller than 20 microns resemble spectra for Martian bright regions, while spectra of larger size separates show characteristics in common with spectra for Martian dark regions. Data on the HWMK1 soil are consistent with the partitioning of iron among the following minerals: olivine, titanomagnetite, hematite, and a superparamagnetic colored ferric oxide. These mineralogies are heterogeneously distributed within the soil with respect to both particle type and soil-particle diameter. The strongly magnetic titanomagnetite is associated with black particles and is responsible for the magnetic nature of the soil, while the colored weakly magnetic superparamagnetic ferric oxide and minor hematite are associated with orange particles.

Morris, Richard V.↗
NASA NTRS2012

Large-Strain Transparent Magnetoactive Polymer Nanocomposites

A document discusses polymer nano - composite superparamagnetic actuators that were prepared by the addition of organically modified superparamagnetic nanoparticles to the polymer matrix. The nanocomposite films exhibited large deformations under a magnetostatic field with a low loading level of 0.1 wt% in a thermoplastic polyurethane elastomer (TPU) matrix. The maximum actuation deformation of the nanocomposite films increased exponentially with increasing nanoparticle concentration. The cyclic deformation actuation of a high-loading magnetic nanocomposite film was examined in a low magnetic field, and it exhibited excellent reproducibility and controllability. Low-loading TPU nanocomposite films (0.1-2 wt%) were transparent to semitransparent in the visible wavelength range, owing to good dispersion of the magnetic nanoparticles. Magnetoactuation phenomena were also demonstrated in a high-modulus, high-temperature polyimide resin with less mechanical deformation.

Meador, Michael A.↗
DOE OSTI2014

Functionalized magnetic nanoparticle analyte sensor

A method and system for simply and efficiently determining quantities of a preselected material in a particular solution by the placement of at least one superparamagnetic nanoparticle having a specified functionalized organic material connected thereto into a particular sample solution, wherein preselected analytes attach to the functionalized organic groups, these superparamagnetic nanoparticles are then collected at a collection site and analyzed for the presence of a particular analyte.

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

Green Synthesis of Fe{sub 3}O{sub 4}/Cellulose/Polyvinyl Alcohol Hybride Aerogel and Its Application for Dye Removal

A novel Fe{sub 3}O{sub 4}/cellulose–polyvinyl alcohol (PVA) aerogel was successfully synthesized by an eco-friendly and facile method in this work. Cellulose/PVA matrix was prepared through an environmental friendly physical cross-linking process and further in-situ decorated with Fe{sub 3}O{sub 4}. Series of Fe{sub 3}O{sub 4} decorated aerogels were prepared and the effects of Fe{sub 3}O{sub 4} nanoparticles (NPs) on the aerogels were systematic investigated. As-prepared aerogels exhibited desirable properties including nanostructure, relatively high porosity, improved mechanical and superparamagnetism. The TEM results showed that Fe{sub 3}O{sub 4} NPs were integrated in the three-dimensional matrix of cellulose/PVA with a diameter of 9–12 nm. Furthermore, the mechanical strength of the aerogels was significantly enhanced after the introduction of Fe{sub 3}O{sub 4} NPs. Meanwhile, the obtained Fe{sub 3}O{sub 4}/cellulose/PVA aerogel exhibited excellent adsorption performance toward methyl blue dye, and can be reused through fenton-like catalysts oxidative degradation of organic dye in H{sub 2}O{sub 2} solution. Therefore, they will have a great potential application as eco-friendly and economical adsorbents.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Luteolin-Loaded Spion as a Drug Carrier for Cancer Cell In Vitro

The aim of this study is to determine the cytotoxic and apoptotic effects of newly synthesized folic acid (FA) and luteolin (carboxylated luteolin (CL)) conjugated superparamagnetic nanoparticle (SPION@FA-PEG@CL) on folate receptor positive (FAR (+)) and negative (FAR (−)) cell lines in vitro. Cytotoxicity analysis by real-time cell analyzer system (RTCA) and apoptosis by TUNEL and Annexin assay, Caspase 3/7 activities, and Caspase 3/7 expression level were determined. According to RTCA results, SPION@FA-PEG@CL nanodrug showed higher cytotoxicity against U87, MCF-7, HeLa cell lines in comparison with L929 and A549 cell lines. TUNEL and Annexin assays indicated that SPION@FA-PEG@CL increased the apoptotic and necrotic cell ratio in FAR (+) cell. In L929 and A549 cells, are FAR (−) cell lines apoptotic and necrotic cell ratio was lower than FAR (+) cell lines (U87, MCF-7 and HeLa). Caspase 3 and 7 analyses also showed that SPION@FA-PEG@CL nanodrug have apoptotic and necrotic impact on cell lines, they were higher in FAR (+) cells than FAR (−) cells. According to results, synthesized SPION@FA-PEG@CL can be a novel nanodrug delivery system for in cancer chemotherapy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Magnetic Responses of Divinylbenzene-Fe{sub 3}O{sub 4} Composite Film Deposited by Free Radical Polymerization Method

The study reports some novel information on both production and characterization for the poly [DVB/Fe{sub 3}O{sub 4}] composite film deposited by free radical polymerization method. The composite film consists of a combination of organic phase and magnetite nanoparticles. The magnetization behavior of the poly [DVB/Fe{sub 3}O{sub 4}] composite film was analyzed with both vibrating sample magnetometers (VSM) and a technique of electron spin resonance (ESR). It was found that the ESR study performed at room temperature showed the poly [DVB/Fe{sub 3}O{sub 4}] composite film had strong transition of g{sub eff} ∼2.5 (254 mT) due to the Fe{sup 3+} S-state ions. This g{sub eff} value indicated that the composite film behavior was near superparamagnetism. The VSM results also supported the ESR results.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Dependence of the Magnetic Transition Temperatures T{sub N1} and T{sub N2} and Magnetization Plateau of the 2D Checkerboard Lattice Structure with the Superblock (N,N)

Magnetic properties of the 2D checkerboard lattice structure with the superblock (N,N) were studied using Monte Carlo simulation based on the Ising model. Thermal magnetization and magnetic susceptibility of 2D checkerboard lattice with several superblocks are given. Two magnetic anomalies at collinear-to-spiral transition temperature t{sub C1} and transition temperature t{sub C2}have been determined. We discuss the effect of exchange interactions and superblocks on 2D checkerboard lattice. Magnetic hysteresis cycle of 2D checkerboard lattice for several superblocks have been shown. Superparamagnetic behaviour has been observed. Magnetization plateau, visible as anomalies in magnetic hysteresis, is one of the hallmarks of frustrated magnetism.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Peculiarities of Magnetic States of Iron-Cobalt Coatings Formed on Aluminum by Plasma Electrolytic Oxidation

Ferromagnetic oxide coatings were formed on aluminum alloy by the plasma-electrolytic oxidation technique in an electrolyte with colloidal particles of iron and cobalt hydroxides. Iron and cobalt are concentrated in the coating pores as a part of nanosized crystallites. The size of individual crystallites in the pores was ∼50–100 nm. The deficit of oxygen to form oxides in crystallites shows that the metals in the crystallites are predominantly in a reduced state. It is also possible that the metal or oxide nuclei are surrounded by oxide-hydroxide shells. The coatings obtained within 5 min have a high coercive force H{sub c} = 1300 Oe. A theoretical analysis of the magnetic properties of Fe-, Co-containing coatings has been performed using the model of clusters consisting of magnetostatically interacting particles. The theoretical value of the saturation magnetization and the experimental values of the coercive force can be explained with the presence of two phases in the nanoparticles: a large antiferromagnetic or ferromagnetic (hydroxides and/or oxides of iron and cobalt) and a small superparamagnetic (iron, cobalt, magnetite, maghemite).

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

An Investigation on Magnetic-Interacting Fe{sub 3}O{sub 4} Nanoparticles Prepared by Electrochemical Synthesis Method

Naked, polyvinylchloride (PVC)-coated, and polyethylene glycol (PEG)-coated Fe{sub 3}O{sub 4} nanoparticles (NPs) with an equivalent average particle size of 10 nm were prepared through an electrochemical synthesis method. The structural and magnetic properties were investigated systematically. The X-ray diffraction study coupled with the Rietveld refinement of XRD data showed that samples are crystallized in cubic spinel structure with space group referred to as Fd3m. The nature of DC magnetization versus field M (H) plot for sample resembles qualitatively with ferromagnetic (FM) systems. The AC-susceptibility data obtained at different frequencies confirmed the presence of a frequency-dependent freezing temperature. Based on the interparticle interaction strength and phenomenological models (Néel–Brown, Vogel–Fulcher, and critical slowing down), the magnetic dynamic behavior of nanoparticles was characterized. By fitting the experimental data with mentioned models, the possibility existence of superparamagnetic and a spin-glass state at low temperatures was proposed for the samples. Also, the obtained values from fitting performance showed a coating effect on interparticle interaction for PVC- and PEG-coated Fe{sub 3}O{sub 4} nanoparticles.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Abnormal Transport and Magnetic Properties Induced by Change of the Phase Volume Ratio for YBa{sub 2}Cu{sub 3}O{sub 7-δ}/La{sub 0.67}Sr{sub 0.33}MnO{sub 3} Hybrids

Two elaborately designed hybrids consisting of superconducting YBa{sub 2}Cu{sub 3}O{sub 7-δ} (YBCO) and ferromagnetic La{sub 0.67}Sr{sub 0.33}MnO{sub 3} (LSMO), namely 20 × (YBCO(m)/LSMO(100 − m)) are prepared on single crystal SrTiO{sub 3} (STO) by pulsed laser deposition (PLD) with 20 being repetition periods and m = 90 and 10, respectively, which represents YBCO pulse number in a period. The films show highly c-oriented and epitaxial quality, suggested by XRD 𝜃–2𝜃 scans and pole figures. The 20 × (YBCO90/LSMO10) sample with a large YBCO volume fraction exhibits the typical character of a metal superconductor at about 90 K, while its transition width reaches 9.1 K, which is nearly eight times of that of the pure YBCO film. Above the superconducting transition temperature, a superparamagnetic signal rather than ferromagnetic behavior is observed, which may be associated with a diluted system consisting of the ferromagnetic nanoparticles embedded in the superconducting films. For the hybrid with a small YBCO volume fraction, i.e., the 20 × (YBCO10/LSMO90) sample, its transport behavior at normal state is insulating, and it is found that the Mott variable range hopping conduction dominates in this insulating phase in the temperature range 70–310 K. Obviously distinguishable insulator to superconductor (IS) transition occurs at 52 K, but the superconducting diamagnetic signals are very weak in the magnetic measurements below the IS temperature. For this sample, the magnetization loop at 100 K is ferromagnetic, yet manifested by a reduced coercive field and residual magnetization as compared with a pure LSMO film. In fact, both hybrids represent two kinds of nanocomposites, i.e., superconducting nanoparticles in a ferromagnetic matrix and ferromagnetic nanoparticles in a superconducting matrix, which benefits to study interfacial interactions due to an increased interface to value ratio and reduced size effect.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Magnetic Performance and Evaluation of Radiofrequency Hyperthermia of Perovskite La{sub 1−x}Sr{sub x}MnO{sub 3}

Magnetic nanoparticles (MNPs) can induce localized hyperthermia by alternating magnetic fields, in order to kill cells at tumor sites. In this study, La{sub 1−x}Sr{sub x}MnO{sub 3} nanoparticles with x = 0.2, 0.3, 0.4, and 0.5 were prepared via sol–gel technique. The synthesized nanoparticles were characterized in terms of structure, morphology, and magnetic properties with Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) studies. The average size of nanoparticles was measured to be 57.09, 30.477, 10.24, and 35.982 nm by Williamson–Hall method for x = 0.2, 0.3, 0.4, and 0.5, respectively. The absence of hysteresis in the magnetic response of nanoparticles represents the superparamagnetic behavior. Toxicity test was also performed to evaluate the toxicity concerns of the prepared nanoparticles upon entrance to the body. Furthermore, the alternating current magnetic heating characteristics of La{sub 1−x}Sr{sub x}MnO{sub 3} nanoparticles was also studied, by 1 mg/mL concentration, to test the ability of the nanoparticles as magnetic hyperthermia treatment agents. The magnetothermia were measured in an RF magnetic field of 88 Oe and 430 kHz. The present work reveals that LSMO nanoparticles possess the biocompatible properties for biomedical applications and can provide the required heat at appropriate time.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Synthesis, Spectroscopy, and Magnetic Characterizations of PVP-Assisted Nanoscale Particle

Inverse spinel ferrite of nonmagnetic metal-doped ferro-ferric oxide was synthesized by co-precipitation technique, and its characterizations have been performed by XRD, FTIR, TEM, EDX, VSM, and EPR. XRD figures show the prepared samples in their cubic phase and that their crystallite faces vary from 5.57 to 18.47 nm. FTIR spectra of the as-synthesized samples were performed in the range of 400 and 4000 cm{sup −1} and annealed at 600 {sup ∘}C. The TEM revealed that the syllable construction of the nanoscale particles was agglomerated in their crystalline sample. From VSM study, the sample obtained has a doublet pattern, and ferromagnetic performance was observed from the samples. From EPR spectra, the line shape and the g values obtained for the samples conformed to superparamagnetic resonance due to Mg{sup + 2} ions with a stoichiometric composition. These typical magnetic hypnotic specifications are used for various sensing applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

An Ising Spin-2 Model on Generalized Recursive Lattice: a Monte Carlo Study

The magnetic properties of Ising spin-2 model on recursive p-polygonal structures are studied using Monte Carlo simulations. The thermal magnetization and magnetic susceptibility of recursive 1-, 2-, 3-, and 4-polygonal structures have been terminated. The variation of magnetization and magnetic susceptibility of recursive 2-polygonal structures for several external magnetic field and the variation of magnetization and magnetic susceptibility versus the crystal field and temperatures of recursive 1-, 2-, 3-, and 4-polygonal structures are given. Finally, the magnetic hysteresis cycle of recursive 1-, 2-, 3-, and 4-polygonal structures are obtained and for different temperatures with 2-polygonal structures. It is shown that the reduced transition temperature increases with increasing the p-polygonal structures and decreases with increasing the absolute value of crystal field. The magnetic coercive field increases with increasing the p-polygonal structures and decreases with increasing the temperature values. The superparamagnetism behavior is observed in our system at around reduced transition temperature.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

The Effect of Folic Acid- and Caffeic Acid-Functionalized SPION on Different Cancer Cell Lines

In this study, caffeic acid (CFA)- and folic acid (FA)-conjugated superparamagnetic iron oxide bio-nanocomposite (SPION@PEG-FA-@CFA) was prepared and its cytotoxic and apoptotic effects against murine fibroblast (L929), glioblastoma (U87), adenocarcinoma, human breast cancer (MCF-7), epithelioid cervix carcinoma (HeLa), and lung carcinoma (A549) have been determined. A real-time cell analyzer system (RTCA) for cytotoxicity, annexin assay and TUNEL, caspase 3/7 expression level, and caspase 3/7 activities for apoptosis were used. The RTCA showed that the cytotoxic effects of the bio-nanocomposite were higher in U87, MCF-7, and HeLa cells (which are folic acid-positive cells (FAR (+))). TUNEL, annexin, and caspase assay results indicated that the bio-nanocomposite caused apoptotic and necrotic impacts on cells. Necrotic and apoptotic cell ratios in FAR-positive cells (L929 and A549) were lesser than those in U87, MCF-7, and HeLa cells (FAR (+)). Therefore, the obtained results showed that the bio-nanocomposite can be used as a nano-medicine for biomedical application (cancer treatments). Moreover, this work can also be useful for designing other functionalized materials which could act as biomaterial. This study will be also informative for the researchers to design novel materials for biomedical applications.

60 APPLIED LIFE SCIENCES↗