Synthesis and Characterization of Antiferromagnetic Kmnf3 Nanoparticles

1999 ◽  
Vol 577 ◽  
Author(s):  
C. Sangregorio ◽  
E. E. Carpenter ◽  
C. J. O'connor
Keyword(s):  
Magnetic Properties ◽  
Reverse Micelles ◽  
Exchange Coupling ◽  
Hysteresis Loops ◽  
Size Control ◽  
Synthesis And Characterization ◽  
Uniform Size ◽  
Average Size ◽  
Aqueous Core

ABSTRACTThe magnetic properties of nanosized antiferromagnetic particles of KMnF3 are presented. The particles were synthesized using the microemulsion technique, i.e. by using the aqueous core of reverse micelles as constrained microreactors for the precipitation of the particles. The structural characterization of the samples, accomplished by TEM and XRD, reveal that the samples consist of cubic-shaped, crystalline KMnF3 nanoparticles of uniform size. Control over the average size of the particles was achieved by changing the reaction time. Four different samples of average size in the range 13-35 nm were prepared. DC magnetic susceptibility measurements revealed superparamagnetic behavior of the particles. Hysteresis loops measured after field cooling the samples through TN were shifted. The shift is ascribed to the exchange coupling between the antiferromagnetic core of the particles and the uncompensated spin shell surrounding it.

Preparation and characterization of ultrafine TiO2 particles in reverse micelles by hydrolysis of titanium di-ethylhexyl sulfosuccinate

1998 ◽  
Vol 13 (5) ◽  
pp. 1249-1254 ◽  
Author(s):  
Manjari Lal ◽  
Vishal Chhabra ◽  
Pushan Ayyub ◽  
Amarnath Maitra
Keyword(s):  
Reverse Micelles ◽  
Synthesis And Characterization ◽  
Structure Parameters ◽  
Aerosol Ot ◽  
Tio2 Particles ◽  
Ion Exchange Reaction ◽  
Aqueous Core ◽  
Hydrolysis Of ◽  
Ultrafine Tio2

We describe the synthesis and characterization of ultrafine TiO2 particles (in both anatase as well as rutile form) produced by a chemical reaction within the aqueous core of a water-in-oil microemulsion. The microemulsion was stabilized and the Ti4+ ions provided by a functionalized surfactant derived from the commercially available Aerosol-OT, i.e., sodium bis (2-ethylhexyl) sulfosuccinate (Na-DEHSS). The Na+ ions in Aerosol-OT were completely replaced by Ti4+ through an ion-exchange reaction in nonaqueous solvents. Ultrafine TiO2 particles were produced by the hydrolysis of the Ti-containing surfactant in the water droplets. The dependence of the size of the precipitated TiO2 · xH2O particles on various structure parameters of the microemulsion was studied in detail.

Synthesis and characterization of Au, Pt supported on graphene aerogel catalysts for CO oxidation at low temperature

2021 ◽  
Vol 11 (1) ◽  
pp. 118-122
Author(s):  
Chuyen Phan Thi ◽  
Hang Tran Thi Thanh ◽  
Phong Pham Nam ◽  
Ha Vu Thi Thu
Keyword(s):  
Low Temperature ◽  
Ambient Temperature ◽  
Co Oxidation ◽  
Pt Nanoparticles ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Graphene Aerogel ◽  
Highly Dispersed ◽  
Average Size

Au, Pt supported on graphene aerogel catalysts (PtAu/rGOA) with molar ratio of Pt and Au of 1:1, and total metal concentration of 5 % were successfully synthesized by hydrothermal method.  The obtained catalysts were characterized by Raman, XRD, XPS, HR-TEM, BET. It revealed that Au and Pt nanoparticles with average size of 3 – 5 nm were highly dispersed on aerogel graphene. The activity of these catalysts was tested  in CO oxidation. The results showed that the conversion of CO at ambient temperature was 100% during 25 minutes. Accordingly, PtAu/rGOA could be considered as a potential catalysts for CO oxidation at low temperature.

Synthesis and Characterization of Particle-reinforced Ni/Al2O3 Nanocomposites

2002 ◽  
Vol 17 (6) ◽  
pp. 1412-1418 ◽  
Author(s):  
I. Shao ◽  
P. M. Vereecken ◽  
C. L. Chien ◽  
P. C. Searson ◽  
R. C. Cammarata
Keyword(s):  
Magnetic Properties ◽  
Rotation Rate ◽  
Particle Concentration ◽  
Volume Fraction ◽  
Particle Dispersion ◽  
Nanocomposite Films ◽  
Synthesis And Characterization ◽  
Electrode Rotation ◽  
Deposition Current Density

Nanocomposite Ni/Al2O3 films were electrodeposited from a suspension of Al2O3 nanoparticles in aqueous nickel sulfamate solution. The volume fraction of particles incorporated increased with electrode rotation rate and decreased with deposition current density. The composition, microstructure, hardness, and magnetic properties of these nanocomposite films were characterized. The mechanical strengthening due to particle dispersion in the films was interpreted by considering an Orowan dislocation bowing mechanism. The coercivity of the films increased with increasing particle concentration in the film. The saturation magnetization showed a weak dependence on particle concentration.

Preparation and properties of thienyl and 2,2′-bithienyl substituted cobalt-bis(semiquinone) valence tautomers

2009 ◽  
Vol 87 (4) ◽  
pp. 533-538 ◽  
Author(s):  
Thomas J. O’Sullivan ◽  
Brandon Djukic ◽  
Paul A. Dube ◽  
Martin T. Lemaire
Keyword(s):  
Magnetic Properties ◽  
Synthesis And Characterization ◽  
Electronic And Magnetic Properties ◽  
Valence Tautomers

The synthesis and characterization of two new 2,2′-bipyridine ligands containing 3-ethynylthiophene and 3,3′-diethynyl-2,2′-bithiophene substituents is presented, along with the preparation, electronic, and magnetic properties of mono- and bimetallic cobalt-semiquinone valence tautomers containing these ligands.

scholarly journals Nanocrystalline alloys: synthesis and characterization of non-stoichiometric Co2FeAl nanocrystals

2016 ◽  
Vol 94 (4) ◽  
pp. 367-372 ◽  
Author(s):  
Lana T. Huynh ◽  
Stephanie N. Bonvicini ◽  
Arthur C. Pinon ◽  
Simon Trudel
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Magnetic Measurements ◽  
Size Control ◽  
Synthesis And Characterization ◽  
Spintronic Devices ◽  
Transmission Electron ◽  
Metal Acetylacetonate ◽  
Capping Ligands

Non-stoichiometric Co2FeAl nanoparticles are formed by the in-solution thermal decomposition of the corresponding metal acetylacetonate complexes in the presence of capping ligands followed by reduction of the obtained material under an H2-containing atmosphere. Transmission electron microscopy indicates that sub-100 nm nanoparticles are obtained, with reasonable size control. Magnetic measurements indicate that the saturation magnetization, Bloch behavior, magnetization reversal, spin-wave stiffness, and exchange stiffness are all comparable to those observed for bulk and thin-film Co2FeAl, indicating that these nanomaterials are promising for use in nanoparticle-based spintronic devices.

scholarly journals Synthesis and characterization of polyborates templated by cationic copper(II) complexes: Structural (XRD), spectroscopic, thermal (TGA/DSC) and magnetic properties

Polyhedron ◽  
2017 ◽  
Vol 135 ◽  
pp. 247-257 ◽  
Author(s):  
Mohammed A. Altahan ◽  
Michael A. Beckett ◽  
Simon J. Coles ◽  
Peter N. Horton
Keyword(s):  
Magnetic Properties ◽  
Synthesis And Characterization

Synthesis and Characterization of Cu2FeSnS4 Semiconductor Nanocrystals with Zincblende Structure

2012 ◽  
Vol 512-515 ◽  
pp. 2019-2022 ◽  
Author(s):  
Xiao Lu Liang ◽  
Xian Hua Wei
Keyword(s):  
Random Distribution ◽  
Semiconductor Nanocrystals ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Nir Absorption ◽  
Average Size

Cu2FeSnS4semiconductor nanocrystals with zincblende structure have been successfully synthesized by a hot-injection approach. Cu+, Fe2+, and Sn4+cations have a random distribution in the zincblende unit cell, and the occupancy possibilities are 1/2, 1/4 and 1/4, respectively. Those nanocrystals were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectroscopy (EDS), and UV-Vis-NIR absorption spectroscopy. The Cu2FeSnS4 nanocrystals have an average size of 7.5 nm and a band gap of 0.92 eV.

Synthesis and Characterization of the First 1:2 Ordered Perovskite Ruthenate

2002 ◽  
Vol 718 ◽  
Author(s):  
Job Rijssenbeek ◽  
Sylvie Malo ◽  
Takashi Saito ◽  
Vincent Caignaert ◽  
Masaki Azuma ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Neutron Diffraction ◽  
Structure Type ◽  
Synthesis And Characterization ◽  
Neutron Diffraction Data ◽  
X Ray ◽  
Relationship Of ◽  
The Relationship ◽  
Perovskite Lattice

AbstractPerovskite-like mixed metal ruthenates are of interest owing to their varied electronic and magnetic properties, which are heavily dependent on the ordering of the transition metals. We report the synthesis and structural characterization of the first 1:2 ordered perovskite ruthenate, Sr3CaRu2O9. The structure was determined from a combination of powder X-ray, electron and neutron diffraction data and is characterized by a 1:2 ordering of Ca2+ and Ru5+ over the sixcoordinate B-sites of the perovskite lattice. Sr3CaRu2O9 is the first example of this structure-type to include a majority metal with d electrons (Ru(V), d3). The relationship of this material to the K2NiF4-type Sr1.5Ca0.5RuO4 (i.e., Sr3CaRu2O8) highlights the dramatic effects of the ruthenium valence on the resultant structure. Remarkably, these two structures can be quantitatively interconverted by the appropriate choice of reaction temperature and atmosphere.

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