The paper reports the synthesis and characterization of a copper ferrospinel thin layer. The thin layer (25 nm) was synthesized by RF sputtering of a pure CuFe 2 O 4 target. The material structure and microstructure were characterized using X-ray diffraction and transmission electron microscopy. Simplified test substrates were microfabricated with interdigitated Pt electrodes to investigate electrical properties in a controlled atmosphere. The sensitive layer was stabilized by annealing at 550 • C under air. NO 2 responses at a low concentration (<1 ppm) and 50% relative humidity were measured between 100 and 500 • C. The optimal response was obtained at 250 • C.