Spinel thin films were prepared by the spin spray technique to develop new thermal imaging materials annealed at low temperature for uncooled microbolometer applications. The spinel thin films were deposited from $[(Ni_{0.30}Co_{0.33}Mn_{0.37})_{1-x}Cu_x]_3O_4$ ($0.1{leq}x{leq}0.2$) solutions and then annealed at $400^{circ}C$ for 1 h in argon. Effects of Cu content (x) and deposition time on the electrical properties of the annealed films were investigated. With increasing deposition time, the resistivity of the annealed films increased. For the annealed films deposited for 1 min, the resistivity of x=0.15 films was lower than that of x=0.1 films due to the different grain sizes. The high temperature coefficient of resistance (TCR) of the annealed films could be obtained at temperature below $50^{circ}C$. Typically, the resistivity of $127{Omega}{cdot}cm$ and TCR of -5.69%/K at $30^{circ}C$ were obtained for x=0.1 films with deposition time of 1 min annealed at $400^{circ}C$ for 1 h in argon.