Neodymium substitution effects in sol-gel derived Y3−xNdxAl5O12

► The Y3−xNdxAl5O12 samples were prepared by simple an aqueous sol-gel method. ► The total substitution of yttrium by neodymium does not proceed in the Y3Al5O12. ► Pure cubic garnet phase is forming only at low concentration of neodymium (x ≤ 1.5). ► The critical value of mean cationic radius in the dodecahedral position is ∼0.94 Å. ► The plate-like crystals consisted of nanograins less than 100 nm have formed.