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

Denis N Karimov,Pavel A Popov,Anna G Ivanova,Nikolay I Sorokin,Natalia A Arkharova,Alexander G Savelyev,Irina I Buchinskaya

doi:10.3390/cryst11030285

Denis N Karimov, Pavel A Popov + Show 5 more

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https://doi.org/10.3390/cryst11030285

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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.

Highlights

Crystalline materials are the basis of any optical and optoelectronic device
Among complex inorganic fluorides based on rare-earth ions, KR3 F10 single crystals with a cubic structure attract special attention as promising materials for optics and photonics [1,2,3,4]
Bulk KR3 F10 (R = Y, Tb) single crystals were successfully grown by the Bridgman technique

Summary

Introduction

Crystalline materials are the basis of any optical and optoelectronic device. The possibility to grow bulk crystals with unique fundamental properties determines the functionality of the instrumentation, practical technological applications, and common progress in science and industry. KY3 F10 (KYF) single crystals, as the best studied representatives of this large KR3 F10 family, have acquired practical importance as a construction optical material and a laser matrix for various rare-earth ion doping [4,5,6,7,8,9,10,11,12,13,14,15]. KTb3 F10 crystals are of interest as a high power converter phosphor for LEDs and a potential candidate for X-ray slow scintillating applications [20]

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