CuO Nanoparticles as a Room Temperature Dilute Magnetic Giant Dielectric Material

We report the structure, magnetic and dielectric properties of CuO nanoparticles synthesized by co-precipitation method. The magnetic measurements reveal the presence of a ferromagnetic (FM) component at room temperature with coercivity of 200 Oe and saturation magnetization of 0.004 emu/g. The observed FM may originate from different valence states of the copper ions due to the oxygen vacancies at the surface/or interface of the particles. In addition, these nanoparticles also exhibit a high dielectric permittivity (ε^´ ~ 10⁴) with weak temperature dependence in a wide range of temperature. Such a room temperature FM and giant dielectric permittivity without the presence of any transition metal could be a very good option for a class of spintronics.