Growth Peculiarities and Properties of KR3F10 (R = Y, Tb) Single Crystals

Abstract

Cubic KR3F10 (R = Y, Tb) single crystals have been successfully grown using the Bridgman technique. Growth of crystals of this type is complicated due to the hygroscopicity of potassium fluoride and melt overheating. The solution to the problem of oxygen-incorporated impurities has been demonstrated through the utilization of potassium hydrofluoride as a precursor. In this study, the crystal quality, structure features, and optical, thermal and electrophysical properties of KR3F10 were examined. Data on the temperature dependences of conductivity properties of KTb3F10 crystals were obtained for the first time. These crystals indicated thermal conductivity equal to 1.54 ± 0.05 Wm−1K−1 at room temperature caused by strong phonon scattering in the Tb-based crystal lattice. Ionic conductivities of KY3F10 and KTb3F10 single crystals were 4.9 × 10−8 and 1.2 × 10−10 S/cm at 500 K, respectively, and the observed difference was determined by the activation enthalpy of F− ion migration. Comparison of the physical properties of the grown KR3F10 crystals with the closest crystalline analog from the family of Na0.5−xR0.5+xF2+2x (R = Tb, Y) cubic solid solutions is reported.

Ytterbium-doped KY3F10 as a promising material for optical cryocoolers

“…The top part of both Yb:KYF boules were transparent but the bottom part was milky because of inclusions. These inclusions, also reported in [14], are most likely due to moisture and hydrates since KF is highly hygroscopic. The entire boule of the Yb:YLF crystal was transparent.…”

Preparation of rare-earth doped NaYF4 luminescent nanoparticles by a high-energy ball milling process

“…Single crystal Na 0.40 Y 0.480 Yb 0.108 Er 0.012 F 2.2 (α-NaYF 4 ) and composite Na 0.55 Y 0.360 Yb 0.081 Er 0.009 F 2.10 (β-NaYF 4 ) were grown by the Bridgman technique in a resistive setup. 81 The growth process was performed in a fluorinating atmosphere (high-purity He + CF 4 mixture) employing a graphite heating unit and crucibles. The initial fluoride powders were additionally annealed under vacuum (5 × 10 −3 Pa) at 500 K and melted in a fluorinating atmosphere for purification from oxygen impurities.…”

Спектроскопическое Исследование Кристаллов KY-=SUB=-3-=/SUB=-F-=SUB=-10-=/SUB=-, Активированных Празеодимом

“…При нормальных условиях кристалл KY 3 F 10 имеет кубическую структуру с пространственной группой симметрии Fm−3m [8]. Схематически эта структура показана на рис.…”