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Title of Article Characterization and magnetic properties of SrTi1−xNixO3 nanoparticles prepared by hydrothermal method 
Date of Acceptance 10 October 2016 
Journal
     Title of Journal Physica B: Condensed Matter 
     Standard SCOPUS 
     Institute of Journal 2016 Elsevier B.V. All rights reserved 
     ISBN/ISSN Doi.org/10.1016/j.physb.2016.10.012 
     Volume 2017 
     Issue 504 
     Month October
     Year of Publication 2018 
     Page 31-38 
     Abstract SrTi1−xNixO3 (x=0, 0.05, 0.10 and 0.15) nanoparticles were prepared by the hydrothermal method. All asprepared samples were annealed at 800 °C for 3 h in argon to study the annealing effect on their magnetic properties. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray absorption near edge spectroscopy (XANES), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometry (VSM) were used to study the crystalline structure, morphology, oxidation state and magnetic properties of samples. XRD results indicate a cubic perovskite structure of all samples with the impurity phase of SrCO3 in all as-prepared samples and Ni metal in annealed samples of x=0.10 and 0.15. SEM and TEM images confirmed a cubic shape for all samples with decreasing average particle sizes from 136.8 ± 4.7 to 126.2 ± 6.9 nm for annealed samples upon Ni doping. XANES results revealed the existence of Ni metal in sample of x=0.05 with the oxidation state of +2 for Ni ion in a SrTi0.95Ni0.05O3 sample. XPS results indicated the promotion of oxygen vacancies. VSM results revealed a paramagnetic behavior at room temperature of all asprepared samples. Ni-doped samples exhibited ferromagnetic behavior after annealing in argon with the Curie temperature (TC) above 380 K for a sample with x=0.05 as shown by field cooling (FC) and zero-field cooling (ZFC) measurements. The room temperature ferromagnetism (RT-FM) of ferromagnetic samples was suggested to be originated from Ni metal and F-center exchange (FCE) mechanism due to the promotion of oxygen vacancies in the perovskite structure. 
     Keyword Ni-doped SrTiO3, Hydrothermal method, Annealing effect, Magnetic properties 
Author
587020048-2 Mr. ATTAPHOL KARAPHUN
Science Doctoral Degree

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