A5053573681- Iron oxide chemistry and applications
- Magnetic Properties and Synthesis of Ferrites
- Metallic Glasses and Amorphous Alloys
- Magnetic properties of thin films
- Magnetic Properties of Alloys
- Magnetic Properties and Applications
- Surface Roughness and Optical Measurements
- Glass properties and applications
- Multiferroics and related materials
- Gas Sensing Nanomaterials and Sensors
- Rare-earth and actinide compounds
- Laser Material Processing Techniques
- Minerals Flotation and Separation Techniques
- Characterization and Applications of Magnetic Nanoparticles
- High Entropy Alloys Studies
- Clay minerals and soil interactions
- Mineralogy and Gemology Studies
- Magneto-Optical Properties and Applications
- Magnetic and transport properties of perovskites and related materials
- X-ray Diffraction in Crystallography
- Advanced Condensed Matter Physics
- Copper-based nanomaterials and applications
- X-ray Spectroscopy and Fluorescence Analysis
- ZnO doping and properties
- Pigment Synthesis and Properties
Duquesne University
2014-2024
Bayer (United States)
2001-2011
Universitatea Națională de Știință și Tehnologie Politehnica București
2002
Bayer (France)
2001
Oklahoma State University
1993-1996
Institutul de Fizică Atomică
1991-1993
University of Bucharest
1986-1993
Haematite particles of four different morphologies (polyhedral, platelike, needlelike and disk shaped) were synthesized by the hydrothermal method. The morphology average particle diameter (1.4, 7.4, 0.2, 0.12 μm, respectively) determined transmission electron microscopy combined with diffraction. haematite samples studied Mössbauer spectroscopy in temperature range 4.2–300 K. In all cases, a weak ferromagnetic (WF) phase was present above Morin 230 K found to coexist an antiferromagnetic...
We report variations in the coercivity of CoFe/sub 2/O/sub 4/ nanoparticles as a function particle size, temperature and light intensity. For 30 nm particles, this change was 2300 Oe at 10 K, 120 170 for intensity under 2 milliwatts. The remanent magnetization nearly unchanged by illumination. A simple model optical absorption followed electron transfer between Co/sup 2+/ Fe/sup 3+/ ions is proposed.
Co, Ni, Mn, Cr, and Cu substituted magnetites were prepared by the hydrothermal method at 300 °C, with concentrations ranging from 8.2% to 12.5%. Transmission electron microscopy determined average particle diameter 〈Φ〉 be in hundred of nm range morphological modifications induced various substitutions employed. Hysteresis loop measurements performed determine coercive field Hc, saturation magnetic moment ms. While Hc decreased increasing 〈Φ〉, shape was found play an important role...
Li2FeGeS4 (LIGS) and Li2FeSnS4 (LITS), which are among the first magnetic semiconductors with wurtz-kesterite structure, exhibit antiferromagnetism TN ≈ 6 4 K, respectively. Both compounds undergo a conventional metamagnetic transition that is accompanied by hysteresis; reversible spin-flop dominant. On basis of constant-wavelength neutron powder diffraction data, we propose LIGS LITS collinear structures commensurate incommensurate propagation vectors km = [1/2, 1/2, 1/2] [0, 0, 0.546(1)],...
Ferromagnetic amorphous ribbons (Metglas 2605 CO, Metglas SM, 2826 MB, and 2605-S3A) were exposed isochronally to pulsed-excimer-laser irradiation (\ensuremath{\lambda}=308 nm, \ensuremath{\tau}=26 ns) by employing various repetition rates pulse energies. The effects of laser treatment studied transmission M\"ossbauer spectroscopy scanning electron microscopy. Complementary information was obtained using conversion energy-dispersive x-ray analysis. At moderate values the rate energy,...
Laser ablation deposition has been used to synthesize nanoscale ferrite structures. Our investigations were performed on NiZn and Zn films deposited silicon(100) substrates. Films produced by laser at room temperature annealed 550°C for 1h. Other directly a substrate without subsequent annealing. Complementary x-ray diffraction superconducting quantum interference device magnetometry measurements helped identify the optimum conditions obtaining desired nanoferrite From hysteresis loops 300...
We measured the change in average hyperfine field strength of several high entropy alloys relation to small compositional deviations from equiatomic alloy, FeCoNiCuMn. Mössbauer spectra four psuedo-binary systems, which Mn content is increased and another element was decreased equal measure, reveal discrete peaks distribution that show evidence exchange interactions between magnetic elements alloy. A simple linear regression modelling perturbation when composition altered calculates...
A comparative study of electron-beam and pulsed-laser irradiation effects in metallic glasses has been performed order to understand the relationship between magnetic behavior select variations structural characteristics alloy phases. Samples ${\mathrm{Fe}}_{81}$${\mathrm{B}}_{13.5}$${\mathrm{Si}}_{3.5}$${\mathrm{C}}_{2}$ glass were irradiated with a pulsed excimer laser (\ensuremath{\lambda}=308 nm, \ensuremath{\tau}=10 ns), high-energy electron beam (W=7 MeV), low-energy beams (W=30 50...
Pulsed-excimer-laser irradiation effects ($\ensuremath{\lambda}=308$ nm, $\ensuremath{\tau}=10$ ns) on the magnetic properties and phase composition of ${\mathrm{Fe}}_{66}$${\mathrm{Co}}_{18}$${\mathrm{B}}_{15}$Si metallic glass have been studied by transmission conversion electron M\"ossbauer spectroscopy, scanning microscopy, energy-dispersive x-ray analysis. Depending number applied pulses, excimer laser amorphous was found to induce controlled changes in anisotropy without onset bulk...