Interfacial exchange coupling and defects driven magnetic and optical properties of Co3O4-NiO nanocomposites

• Published in: Physica. B, Condensed matter Vol. 599; p. 412383
• Main Authors: Gupta, Jhalak, Ahmed, Arham S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.12.2020; Elsevier BV
• Subjects: Antiferromagnetism; Cobalt; Cobalt oxides; Crystal defects; Crystallites; Electron paramagnetic resonance; Ferromagnetism; Fourier transforms; HRTEM; Infrared analysis; Magnetic properties; Magnetism; Magnetometers; Nanocomposites; Nanoparticles; Nickel; Nickel oxides; Optical properties; Photoelectrons; Raman spectroscopy; Room temperature; Sol-gel processes; Sonochemical; VSM; X ray photoelectron spectroscopy; XPS; XRD; VSM; XPS; XRD; Nanocomposites; Sonochemical; HRTEM
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2020.412383

In the present investigation, pristine nickel oxide (NiO) and cobalt oxide (Co3O4) nanoparticles have been synthesised by well pronounced sol-gel auto combustion route. A series of Co3O4-NiO nanocomposite with varying NiO concentration from 10% to 40% by weight to Co3O4, has been synthesised using sonochemical route. A qualitative study of structural, optical and magnetic properties of the nanocomposite series of Co3O4-NiO was performed by analysing X-Ray Diffraction, Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Ultra violet Diffuse Reflectance Spectroscopy (UV-DRS), Transmission Electron Microscopy (TEM), X-Ray Photoelectron Spectroscopy (XPS) and Vibrating Sample Magnetometer (VSM) as well as electron paramagnetic resonance (EPR). From XRD measurements, crystalline phases of pure NiO, Co3O4 and their composites have been confirmed. The crystallite sizes determined by Debye Scherer and Williamson Hall methods were found in good agreement. The interplanar spacing has been calculated using HRTEM images for the synthesised samples. Raman analysis confirms the presence of bands and witnesses the formation of the pure and composite samples. From VSM measurements at room temperature M-H curves witnessed the weak ferromagnetism along antiferromagnetic portion in the samples of NiO & Co3O4-NiO nanocomposites whereas Co3O4 is purely antiferromagnetic. Moreover, EPR measurements confirm the presence of unpaired electrons and field resonance decreases with increase in g value with increasing NiO concentration in the composite samples as compared to NiO sample. •The hysteresis loop confirms the weak ferromagnetism due to AFM-FiM coupling in Co3O4-NiO nanocomposites.•All the nanocomposites exhibit bandgap lying in the visible light range.•XRD results reveal the formation of cubic phase of NiO and cubic spinel phase of Co3O4-NiO nanocomposites.•XPS spectra confirm the formation of Co3O4 phase of cobalt oxide.