Synthesis of coral-like structures of Pr–Yb co-doped YIG: Structural, optical, magnetic and antimicrobial properties

Coral-like structures of the Y3–xPrxFe5–yYbyO12, (0.00 ≤ x ≤ 0.04), (0.00 ≤ y ≤ 0.02) compound were synthesized using the sol gel method. Structural investigation certified the YIG cubic crystal structure formation, without any secondary phase. It is shown that, the relatively large ionic radius of the dopant cations results in an expansion of the lattice parameter, variations in the Iona‒O‒Iond angle, Iona‒O, Iond‒O and Ionc‒O bond distances and decrease in the average crystallite size. Fourier transform infrared (FTIR) and Raman measurements are essential to testify the single-phase formation of YIG crystal structure and are observed changes in the stretching and vibrational modes, respectively. The morphological study, energy dispersive spectroscopy (EDS) spectra and textural properties show coral-like structures, peaks associated with Pr3+ and Yb3+ atoms and the effect of dopants on surface area, diameter, and pore volume, respectively. The optical analysis from diffuse reflectance spectra witnessed an increase in the optical gap band, a decrease in Urbach energy and blue shift in the charge transfer, correlated with the expansion of the unit cell due to the dopant's insertion in the YIG structure. A typical ferrimagnetic behavior is exhibited by the Y3–xPrxFe5–yYbyO12 compound. The saturation magnetization (Ms), cubic anisotropy constant (K1) and coercive field (Hc) increase with the Pr3+ cations content, as consequence of their magnetic nature and distribution around of Fe3+ ions due to the coexistence with the Yb3+. Finally, for the first time, antibacterial tests by mean of the direct contact method were performed for YIG co-doped with Pr3+ and Yb3+ and it is shown that, relatively high dosages of Pr3+ cations favored the activity against S. aureus, therefore, a new biological property for YIG doped with rare earths is presented.