Microwave plasma treatment of NiCuZn ferrite nanoparticles: a novel approach of improving opto-physical and magnetic properties

Microwave plasma treatment of ferrite nanoparticles is a least reported method of improving the opto-physical, energy storage and magnetic properties. In this study, a sol–gel method, coupled with auto-ignition route, was adopted for the synthesis of Ni 0.25 Cu 0.25 Zn 0.50 ferrite nanoparticles. Some of the samples were given low-pressure microwave plasma treatment and the corresponding opto-physical and magnetic properties were compared with the pristine NiCuZn ferrite samples. The pristine and plasma-treated samples were characterized using X-ray diffraction, field emission scanning electron microscope, photoluminescence spectroscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometer. Phase analysis revealed a single-phase face centered ( fcc ) cubic spinel structure of the prepared ferrite samples. The microwave plasma treatment enhances the average crystallite size of the ferrite samples. Surface study reflects agglomeration of the particles in the pristine samples and high porosity in the plasma-treated samples. NiCuZn ferrite possessed photoluminescence characteristics and exhibited a red emission band in the range of 646–647 nm for both pristine and plasma-treated samples. The amplitude of photoluminescence peaks increased on plasma treatment of the ferrite samples, while the energy bandgap remained unchanged. Fourier transform infrared spectroscopy revealed the presence of NO 3 , H–O–H, C–H, and C–O functional groups on the ferrite structure. The saturation magnetization ( M s ) increased from 32.16 to 53.36 emu/g after plasma treatment of NiCuZn ferrite samples.