Cobalt-doped ZnO nanoparticles and PLD-deposited thin film forms: structure, optical properties and nature of magnetic anisotropy

• Published in: RSC advances 2024-08, Vol.14 (38), p.27622-27633
• Main Authors: Khlifi, N, Ihzaz, N, Toulemonde, O, Dandre, A, Labrugère-Sarroste, C, Bessadok, M. N, Lemine, O. M, El Mir, L
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Chemical Sciences; Crystal defects; Crystallites; Electrons; Ferromagnetic materials; Glass substrates; High resolution electron microscopy; Magnetic anisotropy; Magnetic properties; Material chemistry; Mathematical morphology; Nanoparticles; Optical properties; Percolation; Photoelectrons; Pulsed laser deposition; Pulsed lasers; Raman spectroscopy; Sol-gel processes; Spectrum analysis; Texturing; Thin films; Wurtzite; X ray photoelectron spectroscopy; Zinc oxide; Zinc oxides
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d4ra05021e

Cobalt-doped zinc oxide nanoparticles (NPs) were synthesized using a modified sol-gel method. Thereafter, the obtained powder was deposited on a Suprasil glass substrate by employing a pulsed laser deposition (PLD) technique. X-ray diffraction analysis with Rietveld refinement confirmed a hexagonal wurtzite ZnO phase belonging to the P 6 3 mc space group for both samples in the NP and thin film forms. In particular, the thin film exhibited an intensive (002) XRD peak, indicating that it had a preferred c -axis orientation owing to the self-texturing mechanism. No segregated secondary phases were detected. The crystallite structure, morphology, and size were investigated using high-resolution transmission electron microscopy (HRTEM). To study the crystalline quality, structural disorder, and defects in the host lattice, we employed Raman spectroscopy. UV-vis-NIR spectroscopy was performed to confirm the nature of the Co-doped ZnO NP powder and the film. The chemical states of oxygen and zinc in the thin film sample were also investigated via X-ray photoelectron spectroscopy (XPS). The M - T curve could be successfully fitted using both the three-dimensional (3D) spin-wave model and Curie-Weiss law, confirming the mixed state existence of weak ferromagnetic (FM) and paramagnetic (PM) phases. Magnetic interaction was quantitatively studied and explained by polaronic percolation of bound magnetic polarons (BMPs). Analysis of magnetic symmetry of the topological antiferromagnetic as-deposited thin film using torque measurements was performed. Based on a phenomenological model, it was revealed that the structure gives rise to uniaxial magneto-crystalline anisotropy (UMA) with the magnetic easy axis parallel to the c -axis. Cobalt-doped zinc oxide nanoparticles (NPs) were synthesized using a modified sol-gel method.