Synthesis and Characterization of LaNi_0.5Ti_0.5O₃ and La₂NiTiO₆ Double Perovskite Nanoparticles

In the present work, LaNi_0.5Ti_0.5O₃ and La₂NiTiO₆ nanoparticles were synthesized by the modified Pechini method. LaNi_0.5Ti_0.5O₃ was calcined at 1073 K for 17 h or 100 h, while La₂NiTiO₆ was calcined at 1273 K for 135 h. The double perovskite calcined at 1073 K for 17 h presented orthorhombic symmetry with Pbnm space group, mean particle size was 31.9 ± 1 nm, random ordering of Ni²⁺ and Ti⁴⁺ cations, Néel temperature close to 15 K, and magnetic moment of 1.29 μB. By increasing the calcination time, this material showed the same symmetry and space group, a mean particle size of 50.7 ± 2 nm, short-range ordering of Ni²⁺ and Ti⁴⁺ cations, Néel temperature around 12 K, and magnetic moment of 0.96 μB. La₂NiTiO₆ presented a monoclinic crystal structure, with P2₁/n space group, mean particle size of 80.0 ± 5 nm, rock salt ordering of Ni²⁺ and Ti⁴⁺, Néel temperature of approximately 23 K, and magnetic moment of 2.75 μB.