Effect of Mn doping on the microstructure and magnetic properties of CuFeO ceramics

The effects of Mn doping on the microstructure and magnetic properties of CuFeO2 systems were studied using X-ray diffraction（XRD）, X-ray photoelectron spectroscopy, scanning electron microscopy（SEM）, and a physical property measurement method. The microstructure measurements demonstrated that the substitution of Mn for Fe can cause lattice distortion, promote grain growth, and change the valence state of Fe and Mn ions. Ceramic samples with doping content x = 0.00–0.03 exhibited two successive magnetic transition temperature（TN） at TN1 ≈ 14 K and TN2 ≈ 10 K. TN decreased gradually with the Mn4+ content, and TN2 was not observed in the x > 0.05 samples within a temperature range of T = 5–300 K. Magnetic hysteresis loops revealed that only anti-ferromagnetic behavior occurred in the low-doped samples（x = 0.00–0.03）, and the coexistence of ferromagnetism and anti-ferromagnetism was observed in the high-doped samples（x = 0.05–0.10）. Besides, the x = 0.10 sample had a maximum magnetization of 5.98 emu/g. This study provides basic experimental data for investigating the relationship between the microstructure and magnetic properties of CuFeO2 systems.