Microstructure, revealed by X-ray diffraction, transmission electron microscopy and Moessbauer spectroscopy, and magnetic properties such as magnetic susceptibility, its disaccommodation, core losses ...and approach to magnetic saturation in bulk amorphous (Fe sub(0.61Co) sub(0).10Zr sub(0.025Hf) sub(0).025Ti sub(0.02W) sub(0).0 2B sub(0.20)) sub(1)00-xY sub(x (x=0, 2, 3 or 4) alloys in the as-cast state and after the annealing in vacuum at 720 K for 15 min. are studied. The investigated alloys are ferromagnetic at room temperature. The average hyperfine field induction decreases with Y concentration. Due to annealing out of free volumes its value increases after the heat treatment of the samples. The magnetic susceptibility and core losses point out that the best thermal stability by the amorphous (Fe) sub(0).61Co sub(0.10Zr) sub(0).025Hf sub(0.025Ti) sub(0).02W sub(0.0 2B) sub(0).20) sub(97Y) sub(3) alloy is exhibited. Moreover, from Moessbauer spectroscopy investigations it is shown that the mentioned above alloy is the most homogeneous. The atom packing density increases with Y concentration, which is proved by the magnetic susceptibility disaccommodation and approach to magnetic saturation studies.
Quadratic electrooptic coefficient (QEOC) measurements have been made for fullerene C
60
) and its derivative C
60
-2-thioxo-l,3-dithiole. An anomaly in C
p
has been revealed at about - 60°C that ...corresponds to the appearance of a structural phase transition. Correlation with a temperature anomaly in the QEOC is revealed. This leads to the conclusion that the QEOC for fullerene depends mainly on vibrational and rotational contributions. The contribution arising from charge distribution asymmetry is most important in the fullerene derivative. The observed temperature anomalies of the QEOC result in the possibility of using the QEOC as a sensitive tool for observing low-temperature phase transitions in the fullerene derivatives.
We have synthesized Li
2O–Nb
2O
5–ZrO
2–SiO
2 glasses and subsequently crystallized them with different CuO contents (0–0.3
mol% in the steps of 0.05) as nucleating agents and characterized them by ...XRD, SEM and DSC. We have also studied IR, Raman, ESR, optical absorption photoluminescence and dielectric properties to explore the influence of copper valance states and their coordination with oxygen on structural and optoelectronic aspects of the samples. These studies have indicated that there is a possibility for the copper ions to exist in Cu
+ and Cu
3+ states (in addition to Cu
2+ state) in these glass ceramics and participate in the glass network forming. Finally, we have undertaken photoinduced second harmonic generation studies (after the samples were dc field treated at elevated temperatures) with 10
ns Er:glass laser (of wavelength 1540
nm with power densities up to 1.5
GW/cm
2) to examine the suitability of these materials for optically operated devices. The analysis of the results of non-linear optical studies has shown that 0.2
mol% of CuO is the optimal concentration for getting the highest values of second order susceptibility coefficients.
In the Reference 1 it was established that single crystals of guanidine compound C(NH2)34Cl2SO4 possess two structural phase transitions of the first order at T = 352 K (to the intermediate ...orthorhombic) and T= 356 K (to the paraelectric tetragonal). In this report we present results of DSC measurements in heating-cooling regime with relatively low temperature rates- 0.3 K/min and 0.1 K/min. We compare the measured by us the DSC results with temperature dependent photo induced second harmonic generation (PISHG) data. The investigations show that at lowest heating temperature changes velocity (0.1 K/min) we obtain two wide peaks temperature separated. We conclude from this DSC measurement that C(NH2)34Cl2SO4 single crystals undergo a two-step phase transitions. We have received a similar temperature splitting of the observed phase transformations and a 15 K shift between the temperature PISHG dependences and the principal DSC maxima.
PbO–Sb
2O
3–B
2O
3 glasses mixed with different concentrations of TiO
2 (ranging from 0 to 1.5
mol.%) were synthesized. The samples are characterized by X-ray diffraction, scanning electron ...microscopy and DSC techniques. A variety of properties, i.e. optical absorption, photoluminescence, infrared, ESR spectra, magnetic susceptibility, photo-induced birefringence (PIB) and dielectric properties (constant
ɛ′, loss tan
δ, a.c. conductivity
σ
ac over a wide range of frequency and temperature) of these glass–ceramics have been explored. The analysis of these results indicated that Ti ion surrounding ligands play principal role in the observed PIB and the sample crystallized with 0.8
mol.% of TiO
2 is the most suitable for the applications in non-linear optical devices.
PbO-Sb@@d2@O@@d3@-B@@d2@O@@d3@ glasses mixed with different concentrations of TiO@@d2@ (ranging from 0 to 1.5 mol.%) were synthesized. The samples are characterized by X-ray diffraction, scanning ...electron microscopy and DSC techniques. A variety of properties, i.e. optical absorption, photoluminescence, infrared, ESR spectra, magnetic susceptibility, photo-induced birefringence (PIB) and dielectric properties (constant @@ivar epsilon@', loss tan @@id@, a.c. conductivity @@isigma@@@dac@ over a wide range of frequency and temperature) of these glass-ceramics have been explored. The analysis of these results indicated that Ti ion surrounding ligands play principal role in the observed PIB and the sample crystallized with 0.8 mol.% of TiO@@d2@ is the most suitable for the applications in non-linear optical devices.
Diethylammonium tetrachlorcuprate NH
2(C
2H
5)
2CuCl
4 (DEA-CuCl
4) nanoparticles with sizes about 10
nm were synthesized and embedded into the PMMA polymer matrices. Using DSC temperature study a ...substantial influence of the polymer matrix on the phase transition temperatures was shown, reflecting a disturbing effect of principal 3d Cu–3p Cl metal–ligand charge transfer bands. Dependence of the absorption spectra on the nanocrystallites (NC) concentration was studied. It was established that an increase of the NC content results in spectral shift of CuCl
4 absorption bands. Explanation of this phenomenon has been suggested within a framework of first principle crystal field quantum chemical calculations.
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