نتایج جستجو برای: paramagnetic materials
تعداد نتایج: 445890 فیلتر نتایج به سال:
magnetic cofe2o4 nanoparticles were synthesized via a simple chemical reaction using precipitation method. the obtained materials consist of ferrite particles with average diameter of 25 nm. the effect of different surfactants such as cationic, anionic and neutral on the morphology of the products was investigated. scanning electron microscopy was used to study the structure and particle size o...
in this study, fe 3 o 4 superparamagnetic nanoparticles were synthesized and stabilized by chitosan. then the nanoparticles were characterized by fourier transform infrared spectroscopy and transmission electron microscopy (tem). particle size distribution and zeta potential of the particles also was assessed using malvern zetasizer. the paramagnetic behaviors of the uncoated and chitosan coate...
The first photocontrollable magnetic nanoparticles containing CdS and Prussian blue (PB) have been created using reverse micelles as nanoreactors. Photoinduced electron transfer from CdS to PB in the reverse micelle changed the magnetic properties of the composite nanoparticles from ferromagnetic to paramagnetic. The magnetization in the ferromagnetic region below 4 K was substantially decrease...
A system presenting an antiferromagnetic (AF) phase of single-chain magnets (SCMs) is studied at low temperatures. The phase diagram is first discussed to specify the magnitude of the interchain couplings. Then, we show experimentally and theoretically that slow relaxation of the magnetization can still be observed in the AF phase, with a maximum of the relaxation time close to the AF-paramagne...
Dilute magnetic semiconductors (DMS) are envisioned as sources of spin-polarized carriers for future semiconductor devices which simultaneously utilize spin and charge of the carriers. The hope of discovering a DMS with ferromagnetic order up to room temperature still motivates research on suitable DMS materials. Two candidate wide-band gap DMS are Gd:GaN and Co:ZnO. We have used hard X-ray abs...
Many heavy-fermion systems are close to a quantum critical point in that, as pressure is varied, the paramagnetic heavy-fermion phase becomes unstable to a magnetically ordered phase at zero temperature. The superconducting phases all occur within a narrow range of pressures centered around the quantum critical point. In materials such as UGe2, the paramagnetic phase is unstable to a ferromagne...
PURPOSE To differentiate calcification from hemorrhage on the basis of susceptibility at magnetic resonance imaging. MATERIALS AND METHODS Gradient-recalled echo (GRE) phase imaging was performed at 1.5 T in 101 calcified areas (15 in the basal ganglia, 86 out of the basal ganglia) and 39 uncalcified locations (13 choroid plexus and pineal glands, 26 old hemorrhages). Experiments with a small...
Molecular structures of the isolated tetrahedral oxovanadium(IV) and bridged μ-oxo-divanadium(IV) complexes hosted by the clusters mimicking surfaces of amorphous silica-based materials were investigated using density functional theory (DFT) calculations. Principal values of the g and A tensors for the monomer vanadyl species were obtained using the coupled-perturbed DFT level of theory and the...
A small, high resolution paramagnetic susceptibility thermometer was developed using a GdCl3 paramagnetic salt. The device uses a SQUID (Superconducting Quantum Interference Device) magnetometer to determine the temperature dependent magnetization of the salt in a magnetic jield. The magnetic jield is provided by a pair of small samarium cobalt permanent magnet disks situated inside the thermom...
Electron spins in carbon materials, including paramagnetic fullerenes, diamond with NV- centers, and graphene nanoribbons, have long coherence time that is suitable for quantum information applications. In this perspective, we discuss how to harness electron materials. The development of the methods introduce spin combined manipulation readout techniques states, provide a cascade applications r...
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