Visible-light excited polar Dion-Jacobson Rb(Bi1-xEux)2Ti2NbO10 perovskite: Photoluminescence properties and in-vitro bioimaging

Rare-earth ion-activated oxide phosphors are beneficial to overcome the problems like photobleaching, reduced lifetime, and the blinking of organic dyes and quantum dots for bioimaging applications. In this work, we...

Структура электронных состояний соединений Gd-=SUB=-5-=/SUB=-Sb-=SUB=-3-=/SUB=- и Gd-=SUB=-5-=/SUB=-Ge-=SUB=-2-=/SUB=-Sb по данным зонных расчетов и оптической спектроскопии

Results of investigations of the electronic structure and optical properties of Gd5Sb3 and Gd5Ge2Sb compounds are presented. Calculations of band spectra were carried out in frame of local density approximation with a correction for strong correlation effects in 4f shell of rare-earth ion (DFT+U+SO method). Optical constants of these materials were measured by ellipsometric technique in wide wavelength interval. Energy dependencies of a number of spectral parameters were determined. The nature of quantum light absorption is discussed on the base of comparative analysis of the experimental and calculated spectra of optical conductivity.

Химическое сжатие, структурная нестабильность и ИК-активные фононы в ряду редкоземельных аналогов францисита Cu-=SUB=-3-=/SUB=-RE(SeO-=SUB=-3-=/SUB=-)-=SUB=-2-=/SUB=-O-=SUB=-2-=/SUB=-Cl

ATR and transmission spectra of a series of rare-earth francisite-like phases Cu3RE(SeO3)2O2Cl (RE is a rare earth element, RE = Nd, Sm, Eu, Gd, Dy, Ho, Tm, Yb) were studied. The frequencies of the IR-active phonons of the crystals under study were determined. In the dependences of phonon frequencies on the ionic radius in a series of isostructural compounds, two tendencies are observed: a hardening of frequencies due to an increase in chemical pressure and a softening of the vibration frequencies, in which rare-earth ions are involved, due to an increase in the mass of a specific rare-earth ion. In the Cu3Dy(SeO3)2O2Cl crystal, an anomalous softening of low-frequency phonons at low temperatures was observed, which was apparently associated with the structural instability of the compound.

Leaching of Rare Earth Elements from NdFeB Magnets without Mechanical Pretreatment by Sulfuric (H2SO4) and Hydrochloric (HCl) Acids

A simplified approach for rare earth elements leaching from NdFeB (neodymium-iron-boron) magnets was investigated. The possibility of simplifying the magnet recycling process by excluding grinding, milling and oxidative roasting unit operations was studied. Attempts to skip the demagnetization step were also conducted by using whole, non-demagnetized magnets in the leaching process. The presented experiments were conducted to optimize the operating conditions with respect to the leaching agent and its concentration, leaching time, leaching temperature and the form of the feed material. The use of hydrochloric and sulfuric acids as the leaching agents allowed selective leaching of NdFeB magnets to be achieved while leaving nickel, which is covering the magnets, in a solid state. The application of higher leaching temperatures (40 and 60 °C for sulfuric acid and 40 °C for hydrochloric acid) allowed us to shorten the leaching times. When using broken demagnetized magnets as the feed material, the resulting rare earth ion concentrations in the obtained solutions were significantly higher compared to using whole, non-demagnetized magnets.