| Abstract: | Potassium holmium tungstate KHo(WO4)2 crystal, as other tungstates, shows the high temperature irreversible structural phase transition. Owing to this, KHo(WO4)2 single crystals were grown due to spontaneous crystallisation with use of the High Temperature Solution Growth technique, which allows to lower the temperature of crystallisation below the temperature of the phase transition. K2W2O7 was used as a solvent. It provides a very wide temperature range of crystallisation and does not introduce additional impurities into the melt. The starting flux contained 20 mol% of KHo(WO4)2 dissolved in K2W2O7. It was found that potassium holmium double tungstate is pleochroic. The two different optical spectra: one spectrum for electrical vector of linearly polarised light parallel to optical Y axis (main spectrum) and second one for electrical vector perpendicular to Y axis were measured. |
