Narrow Results

The significant role of the chemical environments of rare earths ions in controlling their radiative and nonradiative processes are exemplified in this study: The emission properties of rare earth ions (Dy³⁺ or Tm³⁺) embedded in the strong covalent chalcogenide glass (Ge and/or As containing sulphide glass) are dramatically enhanced upon the addition of very small amount of the Group III elements (Ga or In) and alkali halides (CsBr or RbBr). These compositional adjustments alter only the local structural environments of rare earth ions, while thermal stability of the modified glass is kept unaltered.

Thermally induced spin control is one of the main directions for future spin devices. In this study, we synthesized single-phase polycrystalline ErFe${}_{1-x}$Cr_xO₃ and combined the magnetization curves and Mössbauer spectra to determine the macroscopic magnetism at room temperature (RT). The magnetization of the system at various temperatures is well simulated by molecular field theory. And it is found that under the Dzyaloshinskii–Moriya (DM) interaction, not only the B-site ions undergo a reorientation process, but the spins of the A-site ions also change at the same time. The effective spin is defined as the projection of Er${}^{3+}$ on the Fe${}^{3+}$/Cr${}^{3+}$ spin plane, and the whole reorientation process is obtained by fitting. This study will complement the actual process of ErFe${}_{1-x}$Cr_xO₃ spin reorientation and will lay a theoretical foundation for the fabrication of future spin-controlled devices.

Hybrid graphene oxide (GO) with metal ions have become very promising for many applications including catalyst, thermal conductive paper, magnetic devices, energy storage and electronics. In this paper, GO was mixed with trivalent rare earth ions, LaCl₃ to prepare GO/LaCl₃ hybrid composites. The GO/LaCl₃ hybrid composites were tunable by controlling the ratio of LaCl₃ to GO. The interaction between GO and LaCl₃ includes the coordination of La³⁺ with carboxyl groups at the edges of GO, the coordination of La³⁺ with epoxides and hydroxyls, and the electrostatic force between La³⁺ and aromatic bonds of GO. The La³⁺ preferred the coordination with the oxygen-containing groups of GO sheets first. However, the electrostatic absorption of La³⁺ was the main factor that controls the deposit of GO/LaCl₃ composites. The GO/LaCl₃ hybrid structures were also investigated.

Luminescence of LiNbO₃:Er³⁺ crystal at a wavelength of 1010 nm and 1500 nm under pulsed excitation of different power at a wavelength of 980 nm are experimentally and theoretically studied. It is revealed, that the main part of the absorbed energy gives rise to the luminescence at 1500 nm. Considered concentrations of Er³⁺ impurity ions allow to exclude cooperative processes in the impurity subsystem. The experimental results are interpreted in the framework of a three electronic levels system, assuming that the population of the higher lasing level ⁴I_13/2 in the crystal under study is caused by relaxation processes from the excited level. It is shown that for obtaining of a laser radiation at about 1500 nm one can effectively use a pulse-pumping at 980 nm with a power density in a range of 50 ÷ 60 MW/cm².

In this study, the fluorescence properties of Ferulic acid-Tb³⁺-SDBS system were studied. It was found that the addition of surfactant SDBS could enhance the fluorescence intensity of the system, a new pharmaceutical analytic method for the trace detection of ferulic acid content of drugs was also established. The fluorescence intensity of system with the excitation wavelength of 336nm and the emission wavelength of 545nm was monitored. The results showed that there was a good linear relationship between ferulic acid and the fluorescence intensity of the system while the concentration of ferulic acid in the range of 1×10⁻⁸∼4×10⁻⁶mol/L. The linear equation: If = 22.59 C+36.075, the correlation coefficient: r = 0.997.