Abstract [(Ni 0.2 Mn 0.8 ) 1− x Cu x ] 3 O 4 (0.25≤ x ≤0.4) thin films were fabricated by metal-organic decomposition to develop new thermal imaging materials applicable to microbolometer. Effect of Cu content on the electrical properties of the annealed films was investigated. The microstructures of the annealed films were improved with an increase of Cu content. A single phase of cubic spinel structure was confirmed for the annealed films. With increasing Cu content, the resistivity ( ρ ) of the annealed films decreased due to the improved microstructures. The negative temperature coefficient of resistance (TCR) of the annealed films also decreased with an increase of Cu content. Good electrical properties with values of ρ =30.9 Ω cm and TCR =−3.253%/K at room temperature were obtained in x =0.275 films annealed at 450 °C for 15 h.