Synthesis of (Mn, Fe) co-doped Zn₃P₂ nanoparticles: structural, optical and magnetic properties via solid-state reaction route

Manganese and iron (Mn–Fe) co-doped with zinc phosphide (Zn_(3−(x+y)) Mn_xFe_yP₂, x = 0.02, y = 0.02,0.04,0.06, and 0.08) nanoparticles were synthesised by a solid-state method. Structural, morphological, composition, optical, photoluminescence, and magnetic properties were investigated. The characterization techniques such as XRD (X-ray diffraction), SEM (Scanning electron microscopy), EDS (Energy dispersive X-ray spectroscopy), UV-Vis–NIR spectroscopy (Ultraviolet–Visible near-infrared region), PL (Photoluminescence), and VSM (Vibrating sample magneto meter) were employed to explore the obtained nanoparticles. The XRD analysis revealed that co-doped samples showed a tetragonal structure and no secondary phase peaks were observed in the diffraction patterns. Lattice parameters increase from a = b = 8.0211 Å, c = 11.4048 Å to a = b = 8.1408 Å, c = 11.4629 Å with increasing dopant concentration. The SEM study revealed that the size of agglomerations slightly increases with increasing dopant concentration. The elemental analysis confirmed that all the Mn-Fe co-doped Zn₃P₂ nanoparticles are nearly stoichiometric. The diffuse reflectance spectra were used to calculate the optical bandgap of the Mn-Fe codoped Zn₃P₂ nanoparticles and it increased with increase of dopant concentration (1.412–1.425 eV). PL studies confirmed all emission peaks are in the same wavelength position and slight intensity changes with increasing dopant concentration. The M–H hysteresis loop of the pure and Mn-Fe co-doped Zn₃P₂ nanoparticles shows weak ferromagnetism changing to strong ferromagnetism with the increase in dopant concentration. Magnetic moment obtained from the present studies suggests that the Mn–Fe co-doped Zn₃P₂ nanoparticles may be a useful material in semiconductor spintronics.