Growth Conditions and Some Properties of TmB₄ and TmAlB₄ Single Crystals Obtained from High-Temperature Aluminium Metal Solution

TmB₄ and TmAlB₄ single crystals were obtained by the high-temperature aluminium solution method using thulium oxide powder and crystalline boron powder as starting materials. The optimum conditions to obtained relatively large crystals mentioned above were found to include soaking temperature 1500°C, soaking time 10 h, cooling rate 50°C·h^-1 and the atomic ratios of starting materials: B/Tm=5.5, Al/Tm=119.25 for TmB₄; B/Tm=2.0, Al/Tm=119.25 for TmAlB₄. In the case of TmB₄, polyhedra single crystals were obtained. The ternary single crystals TmAlB₄ were generally obtained in the form of prismatic shape extending in the <001> direction or with well developed (100) faces. The as-grown TmB₄ and TmAlB₄ single crystals were used for chemical analysis and measurements of unit cell dimensions. Densities, microhardness and electrical resistivity of the as-grown crystals was studied.