Photoluminescence features of magnetic nano-metric metal oxides

Copper oxide (CuO) and cobalt oxide (Co₃O₄) nanoparticles (NPs) have been synthesized using microwave irradiation method. These NPs have been prepared using copper nitrate and cobalt nitrate, respectively as the starting materials. The resulted powder of these NPs were explored by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), thermogravimetry and differential thermal analysis (DTA). XRD observations obtained the formation of nanostructure phase for both types of these NPs. The structural observations were helped for identifying the nano nature of these both materials. Optical properties such as photoluminescence (PL) and absorbance (A) of CuO and Co₃O₄ NPs have been studied. A resulted shift of PL with respect to absorption peak is 290 and 172 nm for CuO and Co₃O₄ NPs, respectively. Moreover, the magnetic hysteresis loop of both CuO and Co₃O₄ NPs were measured. The magnetic investigations obtained that the magnetic response with a maximum moment M ≤ 0.07 emu/g is shown up to the maximum applied the field of 5 kOe for CuO NPs which is related to the uncompensated surface spins. On the other hand, the magnetization curve has linear shape in the field range used with the irreversible contribution for Co₃O₄ NPs.