Microstructural, Magnetic, and Optical Properties of Pr-Doped Perovskite Manganite La0.67Ca0.33MnO3 Nanoparticles Synthesized via Sol-Gel Process

Weiren Xia,Xinhua Zhu,Heng Wu,Piaojie Xue

doi:10.1186/s11671-018-2553-y

Abstract

We report on microstructural, magnetic, and optical properties of Pr-doped perovskite manganite (La1 − xPrx)0.67Ca0.33MnO3 (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 MnO6 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 MnO6 octahedron. XPS revealed dual oxidation states of Mn3+ and Mn4+ 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.

Highlights

Kumar et al [33] performed studies on the structural, transport, and optical properties of the (La0.6Pr0.4)0.65Ca0.35MnO3 nanoparticles post-annealed at different temperatures
Perovskite manganites R1 − xAxMnO3 (R = La, Pr, and other rare earth elements, A = Ca, Sr, Ba, and other alkalineearth elements) have received considerable interests during the past decade due to their colossal magnetoresistance (CMR) and potential applications in magnetic storage devices, magnetic sensors, and so on [1–3]
In summary, structural measurements based on X-ray diffraction, TEM, HRTEM, and selected area electron diffraction (SAED) patterns provide information regarding the phase formation and the singlecrystalline nature of the Pr-doping perovskite manganite (La1 − xPrx)0.67Ca0.33MnO3 (LPCMO, x = 0.0–0.5) nanoparticles synthesized via sol-gel process

Summary

Introduction

Kumar et al [33] performed studies on the structural, transport, and optical properties of the (La0.6Pr0.4)0.65Ca0.35MnO3 nanoparticles post-annealed at different temperatures.

Results

Conclusion