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Journal Publication
Title of Article Investigation of structural, morphological, optical, and magnetic properties of Sm-doped LaFeO3 nanopowders prepared by sol–gel method 
Date of Acceptance 18 September 2016 
Journal
     Title of Journal Journal of Sol-Gel Science and Technology 
     Standard SCOPUS 
     Institute of Journal Spinger US 
     ISBN/ISSN DOI 10.1007/s10971-016-4212-z 
     Volume 2017 
     Issue 81 
     Month October
     Year of Publication 2017 
     Page 483–492 
     Abstract Pure orthorhombic phase of La1−xSmxFeO3 (x = 0, 0.1, 0.2, and 0.3) nanoparticles can be obtained by sol–gel method after calcination at 800 °C for 3 h in air. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray absorption near edge spectroscopy, ultraviolet-visible spectroscopy, and vibrating sample magnetometry were used to study the crystal structure, morphology, oxidation state, functional group, optical, and magnetic properties of samples. Pure orthorhombic phase of perovskite structure is confirmed by X-ray diffraction results. Decreasing lattice parameters, crystallite sizes, and cell volumes with increasing microstrains indicate structure distortion due to the substitution of Sm ions with small ionic radius on the La sites in the orthorhombic structure. Scanning electron microscopy and transmission electron microscopy images show a homogeneous distribution of almost spherical nanoparticles with decreasing average particle sizes ranging from 56.48 ± 3.22 to 23.21 ± 4.40 nm for samples of high Sm content. Fourier transform infrared spectroscopy spectra confirm the Fe–O stretching mode in octahedral FeO6 unit of a perovskite structure. X-ray photoelectron spectroscopy and X-ray absorption near edge spectroscopy results indicate the oxidation states +3 of La and Fe ions. The optical band gaps are found to decrease from 2.218 to 1.880 eV with increasing Sm content. vibrating sample magnetometry results show the antiferromagnetic behavior of undoped sample and ferromagnetic behavior for doped samples, affecting by structure distortion and particle size reduction. Interestingly, the coercive field is significantly enhanced from 95.07 Oe (x = 0.1) to 13,062.79 Oe (x = 0.3). Curie temperature (T c) is suggested to be above 400 K. 
     Keyword Sm-doped LaFeO3, Sol–gel method, Optical properties, Magnetic properties  
Author
587020048-2 Mr. ATTAPHOL KARAPHUN
Science Doctoral Degree

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Level of Publication นานาชาติ 
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