The influence of the sintering temperature on optical, magnetic, thermal properties and charge density distribution of NiO ceramics

This work describes the influence of sintering temperature (200 °C, 400 °C, and 1000 °C) on the structural, morphological, optical, and magnetic characteristics of nickel oxide (NiO) ceramics. Comprehensive characterization techniques such as powder X-ray diffraction (PXRD), UV–visible spectrometry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), vibrating sample magnetometry (VSM), and thermogravimetric analysis (TGA) to assess the sintering effects. PXRD analysis confirmed the formation of single-phase cubic NiO structure with the increase in peak intensities and average crystallite size 34 nm, 38 nm and 42 nm at 200 °C, 400 °C and 1000 °C signposted enhanced grain growth. Maximum Entropy Method (MEM) analysis revealed a covalent bonding of NiO ceramics. SEM and EDS analysis showed a well-defined and uniform distribution with elemental purity compositions Ni and O. Optical measurements signposted narrow band-gap energies 3.82 eV, 3.80 eV and 3.61 eV at increasing temperature. Additionally, magnetic characterization by VSM revealed a transition from weak to stronger ferromagnetism with increasing temperature. TGA/DTA demonstrated improved thermal stability in higher sintering temperature with weight loss of 7.58 %, 4.79 % and 3.37 % respectively. These findings accentuate the insights significant role in tailoring NiO ceramics for optoelectronics and nanotechnological applications.