Synergistic effect of trivalent (Gd3+, Sm3+) and high-valent (Ti4+) co-doping on antiferromagnetic YFeO3

Abstract

Monophasic polycrystalline powders of Y1−xRxFe1−(4/3)yTiyO3(R = Sm, Gd;x= 0.05, 0.10, 0.15;y= 0.05) were successfully synthesizedviaa low temperature solid-state synthesis route. The X-ray diffraction and Raman spectroscopy studies indicate that all the calcined powders with R3+(Gd3+, Sm3+) at Y3+and Ti4+at Fe3+sites were crystallized in an orthorhombic phase associated with a change in lattice parameters. The Williamson-Hall method employed to calculate the strain revealed that the strain increased with the increased concentration of dopants ((Gd3+, Sm3+) at Y3+) compared to an increase in the size of crystallites, corroborating the findings of SEM. Analysis of diffuse reflectance spectra indicated a drop in bandgap from 1.93 eV to 1.86 eV and 1.96 eV to 1.91 eV for Gd, Ti co-doping and Sm, Ti co-doping respectively, demonstrating the capacity of the synthesized powders to absorb visible light. Absorbance spectra also revealed the existence of mixed states of Fe3+and Fe4+which was corroborated by XPS studies. The magnetic hysteresis loop analysis at room temperature illustrated that with co-doping, there is a strong enhancement in magnetization as well as coercivity, suggesting a strong transition from anti-ferromagnetic behaviour to ferromagnetic behaviour. Pertaining to the greatly improved optical and magnetic properties with the addition of (Gd3+, Sm3+) at Y3+and Ti4+at Fe3+sites, these materials are anticipated to be of potential use in various applications.