Mobility of lithium ions in the crystal structure of lithium gadolinium molybdate LiGd(MoO4)2

Dielectric spectroscopy was used to show that, for LiGd(MoO4)2, a complex molybdate with a stoichiometric oxygen content and a scheelite-type structure, the electric conduction in a wide temperature range mainly occurs via Li+ ions. The dielectric relaxation in a c-axis-cut single crystal was studied over the temperature range 400-1000 K within the framework of the model of thermal ion jumps. This model yielded a minimum jump length for Li+ ions of 1.32 Å and a height of the potential barrier between the nearest positions of ions of 1.65 eV, a value close to the conduction activation energy below the melting point of the crystal

Optical nonlinearity and dielectric properties of noncentrosymmetric crystals of RE borotungstate family Ln3BWO9

The second harmonic generation method was used to prove the noncentrosymmetric structure of Ln3BWO9 borotungstates for elements of the RE series from lanthanum through gadolinium. The crystals exhibit moderate optical nonlinearity in the absence of phase matching between the radiation of the neodymium laser and its second harmonic. An increase in the optical nonlinearity in the middle of the RE series is caused by a more severe distortion of the WO6 polyhedra in crystals. In the range 500-800 K, Tb3BWO9 crystals exhibit dielectric relaxation, while at higher temperature, they are conductors of the Arrhenius type. Both phenomena were analyzed for the a- and c-cuts of Tb3BWO9 single crystals using the model of oxygen ion transfer over vacancies

Optical nonlinearity and dielectric properties of noncentrosymmetric crystals of RE borotungstate family Ln3BWO9

The second harmonic generation method was used to prove the noncentrosymmetric structure of Ln3BWO9 borotungstates for elements of the RE series from lanthanum through gadolinium. The crystals exhibit moderate optical nonlinearity in the absence of phase matching between the radiation of the neodymium laser and its second harmonic. An increase in the optical nonlinearity in the middle of the RE series is caused by a more severe distortion of the WO6 polyhedra in crystals. In the range 500-800 K, Tb3BWO9 crystals exhibit dielectric relaxation, while at higher temperature, they are conductors of the Arrhenius type. Both phenomena were analyzed for the a- and c-cuts of Tb3BWO9 single crystals using the model of oxygen ion transfer over vacancies

Mobility of lithium ions in the crystal structure of lithium gadolinium molybdate LiGd(MoO4)2

Dielectric spectroscopy was used to show that, for LiGd(MoO4)2, a complex molybdate with a stoichiometric oxygen content and a scheelite-type structure, the electric conduction in a wide temperature range mainly occurs via Li+ ions. The dielectric relaxation in a c-axis-cut single crystal was studied over the temperature range 400-1000 K within the framework of the model of thermal ion jumps. This model yielded a minimum jump length for Li+ ions of 1.32 Å and a height of the potential barrier between the nearest positions of ions of 1.65 eV, a value close to the conduction activation energy below the melting point of the crystal

Synthesis, structure, microstructure, and electrical conductivity of (La,Sr)(Ga,Mg)O3-δ Oxide-ion-conducting ceramics

Oxide-ion-conducting perovskite ceramics (La1-ySry)(Ga1-xMgx)O 3-δ were prepared using hydrated Mg and La salts as starting reagents. X-ray diffraction and IR spectroscopy data demonstrate that the symmetry of the solid solutions changes in the sequence orthorhombic-rhombohedral-cubic with increasing Sr + Mg content. © 2001 MAIK "Nauka/Interperiodica"

Synthesis and properties of La 2(Mo 1 - XM x) 2O 9 (M = Nb, Ta) ionic conductors

La 2(Mo 1 - xM x) 2O 9 (M = Nb, Ta; 0 < x ≤ 0.2) solid solutions were prepared, and their physicochemical and electrical properties were studied. Second harmonic generation measurements indicate that the solid solutions have a noncentrosymmetric structure and undergo a structural phase transition accompanied by a sharp increase in ionic conductivity, similar to that of La 2Mo 2O 9. The transition temperature is found to decrease with increasing Nb or Ta content. The introduction of 5 wt % Nb increases the 800°C conductivity of the material

Phase transitions in the BIMEVOX solid solutions with Me = Ga, Zr

The polymorph phase stability ranges have been studied for the Bi 4V2MexO11-y solid solutions with Me = Ga and Zr at room temperature. The formation of orthorhombic α- (x = 0.0 and 0.05) and β-phases (x = 0.1, 0.15) and tetragonal phase (0.2 ≤ x ≤ 0.3) has been revealed in BIGAVOX solid solutions. In BIZRVOX solid solutions, α-phase exists at x ≤ 0.05, while β-phase exists at 0.1 ≤ x ≤ 0.3. The second order phase transitions at ∼ 308°C (BIGAVOX) and ∼ 270°C (BIZRVOX) have been revealed for solid solutions with x = 0.05 using the SHG and DSC methods. In both systems, the β↔-phase transition temperatures have been found to decrease with increasing x