Czochralski growth of solid solutions of strontium hexagallate with magnesium and zirconium as dopants

Phase diagram studies for the growth of (Mg,Zr):SrGa12O19 crystals

“…In agreement with the Mateika & Laurien paper [15], Fig. 2 shows that the SrGa 12 O 19 liquidus, and hence its crystallization window, is extremely narrow.…”

“…It turns out that again the lower peritectic moves downward, here by 20 K. Even more impressing is that the higher peritectic, which is the upper stability range of the hexagallate phase, shifts by > 60 K upward. As already pointed out by Mateika & Laurien [15], obviously the co-doping with Mg 2+ /Zr 4+ increases the stability range. One can see from Fig.…”

“…Significantly better and larger crystals were obtained by Mateika and Laurien [15]. They stated that the small concentration region in the pseudobinary system where SrGa 12 O 19 crystallizes first (in their paper 0.7730 ≤ x(GaO 1.5 ) ≤ 0.8095, very similar to the data given above) can be increased, if Ga 3+ is substituted partially by small equimolar additions of Mg 2+ and Zr 4+ .…”

“…2 shows that the SrGa 12 O 19 liquidus, and hence its crystallization window, is extremely narrow. Moreover, crystal growth is hampered there by the non-equilibrium crystallization of the neighbor phase SrGa 4 O 7 [15]. As pointed out before, the occasional crystallization of non-equilibrium phases seems to be a general issue of the Ga 2 O 3 -SrO system.…”

“…In the magnetoplumbite crystal structure, the Ga 3+ ions reside in octahedral, bipyramidal, and tetragonal environments, and the fivefold coordinated Ga 3+ is randomly displaced from the center of its trigonal bipyramidal coordination polyhedron along positive and negative directions of the c-axis [1,21,22]. Mateika & Laurien [15] peritectic) disappeared for additive levels around 4%-indicating instability of the hexagallate phase. Not so for equimolar MgO/ZrO 2 doping, which is shown in Fig.…”