Pure and Gd-doped NiO nanoparticles capped by polyvinylpyrrolidone (PVP) were synthesized via the co-precipitation method, with different concentrations (x = 0.000, 0.005 and 0.010). Extensive experimental assessments were conducted to study the structural, optical and magnetic properties of the prepared nanoparticles. The X-ray diffraction patterns depicted the formation of pure NiO phase without impurities, assuring the adequate incorporation of Gd dopants into the lattice. The transmission electron micrographs showed the pseudospherical morphology of the pure and Gd-doped samples, with mean sizes, ranging between 28.09 and 22.84 nm. The vibrational spectroscopies confirmed the purity of the synthesized samples and gave insight into their structural properties. Moreover, the excitation dependence of the photoluminescence emission spectra was noticed due to the particles’ size distribution. Some point defects, as the nickel and oxygen vacancies, were tuned upon the introduction of Gd dopants, leading to enhancements in the optical and magnetic properties. The optimum concentration of Gd dopants was x = 0.005 in Ni_1-xGd_xO nanoparticles since it attained the widened bandgap energy of 3.46 eV and highest saturation magnetization of 0.23 emu/g at an applied field of 20 kG. All the samples demonstrated weak ferromagnetic nature, which was deduced from the M-H loops after subtracting the linear magnetization of the antiferromagnetic contribution. The Belov–Arrot plot showed a second-order magnetic transition from antiferromagnetic to ferromagnetic nature. The improvements in PVP-capped Gd-doped NiO nanoparticles are fruitful for light-emitting devices and spintronic applications.

通过共沉淀法合成了不同浓度（x = 0.000、0.005 和 0.010）。进行了广泛的实验评估以研究制备的纳米粒子的结构、光学和磁性。X 射线衍射图描绘了不含杂质的纯 NiO 相的形成，确保 Gd 掺杂剂充分掺入晶格中。透射电子显微照片显示纯样品和掺 Gd 样品的伪球形形态，平均尺寸在 28.09 和 22.84 nm 之间。振动光谱证实了合成样品的纯度，并深入了解了它们的结构特性。此外，由于颗粒的尺寸分布，注意到光致发光发射光谱的激发依赖性。一些点缺陷，如镍和氧空位，在引入 Gd 掺杂剂后被调整，导致光学和磁性的增强。Gd掺杂剂的最佳浓度为 在 Ni _{1- x} Gd _x O 纳米粒子中x = 0.005，因为它在 20 kG 的外加场下获得了 3.46 eV 的加宽带隙能量和 0.23 emu/g 的最高饱和磁化强度。所有样品都表现出弱铁磁性质，这是在减去反铁磁贡献的线性磁化强度后从 MH 环推导出来的。Belov-Arrot 图显示了从反铁磁性质到铁磁性质的二阶磁跃迁。PVP 封端的 Gd 掺杂 NiO 纳米粒子的改进对于发光器件和自旋电子应用是卓有成效的。