Effect of Gd3+ incorporation on the structural, optical absorption, and magnetic properties of aluminosilicate glasses

In this study, aluminosilicate glasses incorporated with 10 wt% Gd3+ were synthesized using the conventional melt quenching method. X-ray diffraction confirmed the amorphous nature of both pristine and doped samples. Raman analysis revealed that the Qn distribution of SiO4/AlO4 tetrahedra remained essentially unchanged after doping, indicating that Gd3+ incorporation does not significantly alter the glass network's polymerization. Electron paramagnetic resonance (EPR) measurements showed resonance signals for both Fe3+ and Gd3+ ions. The addition of Gd3+ induced a decrease in the peak-to-peak linewidth (ΔHₚₚ) and a shift in the resonance field (Hr) of the Fe3+ signal at g ~ 2.302(3), providing evidence for the onset of antiferromagnetic interactions between Fe3+ and Gd3+ ions and a modification of the Fe3+ local environment. Vibrating sample magnetometry (VSM) revealed that Gd3⁺ incorporation increased the magnetic susceptibility and introduced a ferromagnetic component, quantified as 19% of the magnetic response, compared to the purely paramagnetic/antiferromagnetic behavior of the pristine glass. Optical absorption studied by UV–Vis spectroscopy showed broad bands associated with electronic transitions of Fe3+ and Gd3+, while the optical band gap remained unchanged at approximately 2.6 eV $$\pm 0.02$$ . These findings demonstrate that Gd3+ incorporation significantly tailors the magnetic properties of aluminosilicate glasses introducing ferromagnetic interactions and modifying antiferromagnetic coupling without altering their amorphous structure or fundamental optical band gap, making them promising for magneto-optical applications.