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Highlights • Well-shaped KBa R (BO 3) 2 (R = Gd, Tb, Dy, Ho, Tm and Yb) single crystals were grown by flux method. • The anisotropic magnetic properties of KBa R (BO 3) 2 (R = Gd, Tb, Dy, Ho, Tm and Yb) were studied for the first time. • A good model with R -based triangular lattice was studied here. Abstract Crystals of the KBa R (BO 3) 2 (R = Y, Gd, Tb, Dy, Ho, Tm, Yb and Lu) rare earth borates were grown by spontaneous nucleation from a KF-B 2 O 3 flux. The crystals obtained were typically well-developed hexagonal plates about 1 mm in large dimension. The crystals were used to study the anisotropic temperature and field dependent magnetization of the materials, which are based on ideal triangular planes of magnetic rare earths. All structures were refined in space group R 3 - m by single-crystal X-ray diffraction, and in addition to the equilateral triangular rare earth plane lattice, displayed K/Ba site occupancy disorder. All magnetic compounds reveal dominantly antiferromagnetic spin interactions with no magnetic ordering above 1.8 K. With the exception of KBaGd(BO 3) 2 , magnetic anisotropy was observed for other five magnetic members of the family. The results suggest that KBa R (BO 3) 2 crystals may be of further interest for investigating the magnetic properties of rare earth ions on a triangular lattice. [ABSTRACT FROM AUTHOR]

Single crystals of a series of rare earth borates, A 3 Ln (BO 3) (A = Na, K; Ln = Eu, Tb), were synthesized using a boric acid/hydroxide melt. The Na 3 Ln (BO 3) 2 borates crystallized in the monoclinic system with space group P2 1 /n , and the K 3 Ln (BO 3) 2 borates crystallized in the orthorhombic system with space group Pnma. The luminescence of these borates was investigated under ultraviolet and X-ray excitations for the first time. Radioluminescence (RL) measurements showed K 3 Tb(BO 3) 2 to be the brightest compound, with an integral intensity equal to 55% of the integral emission of Bi 4 Ge 3 O 12 (BGO) powder. [Display omitted] [ABSTRACT FROM AUTHOR]

Single crystals of Ba 3 Na 0.32 Nb 6 O 12 (Si 2 O 7 ) 2 were grown for the first time. The use of an alkali/alkaline earth eutectic flux facilitated the crystal growth. Ba 3 Na 0.32 Nb 6 O 12 (Si 2 O 7 ) 2 , a mixed valent Nb(V)/Nb(IV) compound, crystallizes in the noncentrosymmetric hexagonal space group P -62 m with a = 8.9998(10) Å and c = 7.8119(17) Å. The temperature dependence of the magnetic susceptibility was measured and found to be paramagnetic across the entire 2–300 K temperature range measured. Although noncentrosymmetric, Ba 3 Na 0.32 Nb 6 O 12 (Si 2 O 7 ) 2 was not found to be second harmonic generation active. Ba 3 Na 0.32 Nb 6 O 12 (Si 2 O 7 ) 2 was further characterized by IR and UV/Vis spectroscopies. [ABSTRACT FROM AUTHOR]

We have developed laser grade and highly Yb 3+ -doped cubic rare-earth sesquioxides (RE 2 O 3 , RE = Y, Gd, Lu) single crystals by means of a newly designed high-temperature solution growth method which gives them spectroscopic properties different from those obtained by high-temperature solidification methods. Absorption and emission cross sections, visible anti-Stokes emission, fluorescence decays of the new cubic Gd 2 O 3 :Yb 3+ single crystals are presented and compared to those of Y 2 O 3 :Yb 3+ and Lu 2 O 3 :Yb 3+ crystals. The case of cubic Gd 2 O 3 :Yb 3+ is particularly interesting since its basic spectroscopic properties have never been detailed and we were capable of achieving Yb-doping level as high as 20%. [ABSTRACT FROM AUTHOR]

Solid state light sources with dynamically tunable color temperature in the range of 3000–6000 K with chromaticity coordinates lying on the Planckian black body curve has been designed using mixtures of narrow emissions at 615 nm, 575 nm and 550 nm. These respective emissions lines were generated by individual phosphor crystals of trivalent rare earth (RE 3+ ) species, europium (Eu 3+ ), dysprosium (Dy 3+ ) and terbium (Tb 3+ ) activated calcium sodium molybdenum oxide (Ca 1−2 x Na x MoO 4 :RE 3+ x ), when excited by near-ultra-violet (NUV) light emitting diode (LED) with emission wavelength of 380 nm. Highly luminescent crystals of these compounds have been grown from molten solutions (flux) of molybdenum (VI) oxide. The flux grown crystals exhibit emission intensity 2–4 times more than phosphor powders of the same compounds synthesized by traditional solid-state reactions. An optimum flux to solute ratio of 2.5 and solute dissolution temperature of 1100 °C resulted in the largest size crystals. [ABSTRACT FROM AUTHOR]

A new tantalum silicate, Rb 4 Ta 2 Si 8 O 23 , was synthesized as high-quality single crystals by the high temperature flux growth method. Rb 4 Ta 2 Si 8 O 23 was found to exhibit intense blue luminescence and scintillation as a self-activated luminescent silicate. Rb 4 Ta 2 Si 8 O 23 crystallizes in the triclinic space group P 1 ‾ with lattice parameters of a = 6.8916(2) Å, b = 7.7669(2) Å, c = 11.0018(3) Å, α = 76.3110(10)°, β = 89.2560(10)°, and γ = 71.8090(10)°. The structure consists of corner-sharing SiO 4 tetrahedra forming infinite ribbons connected by isolated TaO 6 octahedra. The synthesis, structure, and optical properties are reported, notably, bright blue scintillation when exposed to X-rays. The scintillation of Rb 4 Ta 2 Si 8 O 23 was quantitatively evaluated by radioluminescence (RL) measurements and was determined to be ∼47% of BGO powder. [Display omitted] • Rb 4 Ta 2 Si 8 O 23 was synthesized using flux crystal growth. • The crystal structure was solved using single crystal X-ray diffraction. • Rb 4 Ta 2 Si 8 O 23 exhibits photoluminescence and scintillation. • Scintillation intensity was quantitatively determined to be 47% of BGO powder from RL measurements. [ABSTRACT FROM AUTHOR]