Effect of Ba2+ Doping on the Structural, Optical, Morphological, and Antioxidant Properties of GdAlO3: A High-Temperature Synthesis Approach

Gadolinium aluminate and barium-doped gadolinium aluminate were prepared by a cost-effective planetary ball milling technique, followed by calcination at 1300°C for 4 h. The doping of Ba into GdAlO3 led to unique structural and surface properties of the samples. The structural, optical, and morphological characteristics of the synthesized materials were analyzed by powder X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FTIR), UV-vis spectroscopy, field emission scanning electron microscope (FE-SEM), and X-ray photoelectron spectroscopy (XPS). The structural phase of the calcinated materials was orthorhombic of the space group Pnma, confirmed by XRD analysis. Rietveld refinement method was used to identify the lattice parameters and R-factors. FTIR spectra showed the metal–oxygen bonds at 654 and 488 cm–1. The optical band gap energy of the materials was calculated in the range from 3.47 to 3.63 eV, using the Tauc plots from UV-vis analysis. The surface morphology and elemental composition of the materials were analyzed using FE-SEM and energy-dispersive X-ray spectroscopy (EDS). The oxidation states of Gd3+, Ba2+, and Al3+ for the prepared materials were evaluated by XPS analysis. Ba-doped GdAlO3 samples exhibited dose-dependent antioxidant activity, achieving highest scavenging potential of 34.1%. The enhanced activity was attributed to barium-induced structural modifications, including increased surface reactivity and oxygen vacancy formation.