Microstructural, Magnetic, and Optical Properties of Pr-Doped Perovskite Manganite La(0.67)Ca(0.33)MnO(3) Nanoparticles Synthesized via Sol-Gel Process

We report on microstructural, magnetic, and optical properties of Pr-doped perovskite manganite (La(1 − x)Pr(x))(0.67)Ca(0.33)MnO(3) (LPCMO, x = 0.0–0.5) nanoparticles synthesized via sol-gel process. Structural characterizations (X-ray and electron diffraction patterns, (high resolution) TEM images) provide information regarding the phase formation and the single-crystalline nature of the LPCMO systems. X-ray and electron diffraction patterns reveal that all the LPCMO samples crystallize in perovskite crystallography with an orthorhombic structure (Pnma space group), where the MnO(6) octahedron is elongated along the b axis due to the Jahn-Teller effect. That is confirmed by Raman spectra. Crystallite sizes and grain sizes were calculated from XRD and TEM respectively, and the lattice fringes resolved in the high-resolution TEM images of individual LPCMO nanoparticle confirmed its single-crystalline nature. FTIR spectra identify the characteristic Mn–O bond stretching vibration mode near 600 cm(− 1), which shifts towards high wavenumbers with increasing post-annealing temperature or Pr-doping concentration, resulting in further distortion of the MnO(6) octahedron. XPS revealed dual oxidation states of Mn(3+) and Mn(4+) in the LPCMO nanoparticles. UV-vis absorption spectra confirm the semiconducting nature of the LPCMO nanoparticles with optical bandgaps of 2.55–2.71 eV. Magnetic measurements as a function of temperature and magnetic field at field cooling and zero-field cooling modes, provided a Curie temperature around 230 K, saturation magnetization of about 81 emu/g, and coercive field of 390 Oe at 10 K. Such magnetic properties and the semiconducting nature of the LPCMO nanoparticles will make them as suitable candidate for magnetic semiconductor spintronics.