We report the influence of annealing temperature (600 °C-1000 °C) on structure, crystallographic phase transition,
morphology, vibrational, and magnetic properties of CuFe₂O₄ nanoparticles synthesized by a facile solgel
auto combustion technique. The as-prepared and 600 °C air annealed samples show cubic spinel structure,
secondary phases of α-Fe₂O₃, and CuO (minute reflections), resulting in inferior magnetic properties. Further,
the 800 °C air annealed sample discloses a structural phase transition from cubic to tetragonal phase and minute
α-Fe₂O₃ secondary phase. This sample exhibits the highest coercivity (HC) 1221.4 Oe and squareness ratio
(MR/M20kOe) = 0.56. On the other hand, the sample annealed at 1000 °C in air reveals superior magnetic properties
(magnetization = 24.5 emu/g & HC = 484.7 Oe) compared to all other samples. The revolution of magnetic
properties with annealing temperature originates from the morphology, cubic to a tetragonal structural
phase transition, c/a > 1, and cation site occupation induced by Jahn–Teller distortion.