Crystal structure, optical, photoluminescence, Raman, and magnetic properties for Sm-doped Cr-Mg-Bi ferrites

Abstract

The current work,A series of rare earth Sm³⁺ ion substituted Cr-Mg-Bi ferrites Cr_0.7Mg_0.2Bi_0.1Sm_xFe_2-xO₄ (x = 0.00, 0.02, 0.04, and 0.06) have beensynthesized by thesol-gel auto-combustion method. The XRD, FESEM, HRTEM,UV–Vis, FTIR, Raman spectroscopy, Photo Luminesce and Magnetic Properties analysis have been used to investigate structural, morphological, optical, Raman spectroscopy, Photo Luminesce and Magnetic Properties. Every sample contains a single-phase spinel structure, as confirmed by XRD.The substitution of Sm³⁺ ions is found to increase the lattice parameter from 8.258 to 8.248 Å.A monotone diffraction peak (311) is visible near small angles of degrees (35.33–35.13). The Debye-Scherrer equation, the nanoparticles' crystallite size ranges from 35.357 to 54.778 nm.FE-SEMs reveal a spherical grain that groups and has a porous form, with particles 38.13–53.28 nmin size.HR-TEM micrographs illustrate spherical morphology and their average particle size decreases from 55.32 to 65.42 nm. The selected area electron diffraction (SAED) pattern confirms the crystal planes which were revealed from XRD calculations.The spinel structure was confirmed by FTIR spectroscopy, which found 414 cm⁻¹ and 516 cm⁻¹ vibrational band at the octahedral and tetrahedral sites.As the concentration of Sm³⁺ rises, the direct and indirect band gap energy values determined from UV–Vis show an increase and decrease.The generated NPs' semiconducting nature is confirmed by the strong correlation between the g-value and particle size change.Photoluminescence (PL) investigation shows that all processed samples have four bands.(i) peak centered at 412 nm, which is near-band edge emission and corresponds to the ultraviolet (UV) band,(ii) The violet band has a high-intensity peak at 434 nm,(iii) The blue band is related to a low-intensity, sharp peak located at 466 nm, and (iv) A broad peak at 502 nm with a very low intensity distinguishes the green band.The Raman spectroscopy investigation revealed that the CMBSF nanoparticles had a mixed spinel structure. The magnetic investigation shows that when the Sm content of ferrites increases, saturation magnetization drops from 39.86 to 33.16 emu/g.The sample's coercivity (Hc) increases from 16.06 to 21.90 KOe with Sm substitution.