Effect of yttrium substitution in Fe-doped ZnO nanoparticles: An EPR study
Abstract
In this work, we investigated the effect of Y3+ inclusion in ZnO nanoparticles doped with Fe3+ synthesized by the sol gel method. Transmission Electron Microscopy (TEM) images showed agglomerated nanostructures with different shapes and average particle size distributions ranging from 6 nm to 44 nm in diameter. Electron Paramagnetic Resonance (EPR) studies of the Zn0.98-yY0.02FeyO (y = 0.00 , 0.02, 0.03 and 0.04) were carried out using X band (9.7 GHz) at room temperature. For undoped ZnO and doped with Y3+, complex line shapes were observed as a result of oxygen vacancies (VO+1). In addition, the Y3+ inclusion provokes an enhancement of the linewidth and the resonance field due to intrinsic defects in the hexagonal structure. This observation is compatible with a shortest relaxation time by reason of the particle size reduction and an extra antiferromagnetic local field as a result of the Y3+ presence. For co-doped ZnO samples, the EPR spectra confirms the presence of Fe3+ and Y3+ at the core Zn sites, altering the lattice strain of the ZnO structure. This result was monitored by the zero-field splitting (ZFS) parameters of the spin Hamiltonian, corroborating a reduction in the Fe - Fe interaction. The presence of Y ions was also confirmed in interstitial sites, resulting in a small g -shift from 4.2 to 4.0 associated with modifications of the rhombic component, E, of the Spin-Hamiltonian. This study contributes to the understanding of structural defects caused by the Y and Fe inclusion in the Wurtzite crystal structure of ZnO, a material with potential applications in spintronic devices.
- Publication:
-
Journal of Magnetism and Magnetic Materials
- Pub Date:
- November 2021
- DOI:
- 10.1016/j.jmmm.2021.168317
- Bibcode:
- 2021JMMM..53868317C
- Keywords:
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- Semiconductors;
- EPR;
- Magnetic interactions;
- Defects;
- Nanoparticles