Controllable synthesis and structure-activity relationship of Ni doping in SmCrO₃ for improved magnetic and dielectric properties

Doping small amounts at the A-site or B-site of SmCrO₃ ceramics is a promising approach for modifying their microstructure, as well as their magnetic and dielectric properties. In this study, polycrystalline ceramics of Sm_1−xNi_xCrO₃ (x = 0, 0.05, and 0.20) and SmCr_1−yNi_yO₃ (y = 0.05, and 0.20) were synthesized via a conventional solid-state reaction. X-ray diffraction validated that all the doped ceramics maintained an orthorhombic crystalline structure consistent with the Pbnm space group. Furthermore, X-ray photoelectron spectroscopy demonstrated the presence of Ni²⁺ ions in the doped specimens. Notably, doping resulted in significant enhancement of low-temperature magnetic properties, particularly in samples doped at the A-site, such as Sm_0.80Ni_0.20CrO₃. Compared with the pristine sample, the maximum magnetization of Sm_0.80Ni_0.20CrO₃ increased by approximately 60.93% and 93.49% in the zero-field cooling and field-cooling modes, respectively, in an external magnetic field of 100 Oe. Furthermore, the dielectric constants of the Ni-doped ceramics initially exceeded that of the pristine sample as the temperature increased. At equivalent doping ratios, A-site doping demonstrated superior performance over B-site doping, including higher magnetization, lower dielectric loss, and enhanced electrical quality factors.