Synthesis, structural, optical and magnetic characterizations of SrTb1−xNixO3 nano particules for x = 0.25 and x = 0.5. Application: optoelectronics devices

Abstract

Perovskite-like structures continue to attract considerable attention due to their industrial significance in developing innovative materials with practical applications across various fields, including white LEDs, solar cells, sensors, and photocatalysts. The advancement of ALnO₃ oxide semiconductor nanostructures with specific optical properties is crucial for the optoelectronics and luminescence industries. In this study, SrTb_1−xNi_xO₃ compounds with x values of 0.25 and 0.5 were synthesized using the sol–gel method. The structural, optical, and magnetic properties of the SrTb_1−xNi_xO₃ compounds (for x = 0.25 and x = 0.5) were assessed through various analyses, including x-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, UV–Vis absorption, and magnetic susceptibility measurements. X-Ray Diffraction studies showed that both compositions, SrTb_0.75Ni_0.25O₃ and SrTb_0.5Ni_0.5O₃, crystallized in an orthorhombic system with the space group Pnma. The morphology and average grain size, as measured by scanning electron microscopy, were approximately 500–600 nm. Elemental analysis using energy-dispersive x-ray spectroscopy (EDX) allowed for the identification of the elemental composition of SrTb_0.75Ni_0.25O₃ and SrTb_0.5Ni_0.5O₃. The effect of 50% nickel substitution in the SrTbO₃ compound has been investigated using Raman spectroscopy, and the findings have been correlated with the perovskite structure. The orthorhombic symmetry (No. 62, \({D}_{2h}^{16}\)) was characterized by several Raman bands associated with the bending and stretching of (Tb/Ni)O₆ octahedra and the presence of oxygen vacancies. UV–visible studies indicated absorption in the blue light region, attributed to the yellow-green color of the samples. The direct optical band gaps for SrTb_0.75Ni_0.25O₃ and SrTb_0.5Ni_0.5O₃ were found to be approximately 1.53 eV and 1.28 eV, respectively. These relatively low values suggest that these materials are semiconductors with promising potential for optoelectronic devices. Additionally, the yellowness of these compounds decreased compared to the parent oxide SrTbO₃ after substituting terbium with nickel. Magnetic susceptibility measurements were conducted for both compounds in a temperature range of 2 K–300 K. Both compounds exhibited antiferromagnetic transitions at 31.46 K for SrTb_0.75Ni_0.25O₃ and at 32.3 K for SrTb_0.5Ni_0.5O₃. Temperature-dependent magnetic susceptibilities were measured under zero-field-cooled (ZFC) and field-cooled (FC) conditions. A slight difference between ZFC and FC was observed below the Néel temperatures for both compounds, indicating the onset of an antiferromagnetic moment below those temperatures.