Molecular dynamic simulations of the liquid structure and fast growth of Y₃Al₅O₁₂

Abstract

Due to yttrium aluminum garnet has many excellent properties, investigation of the liquid structure of YAG at high temperatures is significant for many fields, including crystal nucleation, glass fabrication, and...

Localization effect for doping and collaborative diffusion in Er3+:YAG melt

“…YAG melt also belongs to the network-forming systems connected by cationic polyhedra and has an IRO, which has been proved in our previous studies. 14 In most of the metal oxide melts, coordination units (MO n , M = cations) are formed among the cations, and oxygen ions act as the basic structural unit. 26 Effects of doping Er 3+ into YAG on the coordination unit between cation-anions (Al-O and Y-O pairs) are inconspicuous.…”

“…Obviously, the diffusion of cations in these systems is neither determined by the mass of cations nor affected by the coordination unit, because the mass and the coordination unit for each kind of cation is much different. 14 The collaborative rearrangement between the neighbouring cation polyhedrons led to the diffusion of ions. On the one hand, the starting time of diffusion for each kind of ion is basically the same, as shown in the blue dashed line in Fig.…”

“…The YAG melt consists of coordination units (AlO n and YO n ), which are connected with each other by sharing oxygen ions and forming the network structure. 14 Equal barriers for each kind of cation mean the difficulty for rearrangement of the network structure near the cation coordination polyhedron is the same. This indirectly proves that the collaborative relaxation of the medium-range structures affects ion diffusion.…”

“…13 Our recent simulation results also have demonstrated that indeed there are various cation coordination structures. 14 It is more important that the connected mode between the cation coordination structure has a significant impact on the phase transition or the state of the melt. Due to the similarity between the local structure of the cationic polyhedral connections in the YAG melt and that in YAP (YAlO 3 ), the YAP phase appears during the cooling process in YAG melt, 9,14 which will bring out the inclusions in the YAG crystals and reduce the quality of the crystal.…”

“…The stiffness coefficient k for Er 3+ should be larger than that of Y 3+ , which can counteract the effect of the mass.In the second one, sub-diffusive regime, ions move within a local range under the caging effects. Cations in the YAG melt form a coordination structure (polyhedron) with neighbour O 2− , and the cations are located inside the polyhedron14 which is like a cage. The situation for anions is similar, but surrounded by cations.…”