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Title: Enhanced ferromagnetic properties and high temperature dielectric anomalies in Bi{sub 0.9}Ca{sub 0.05}Sm{sub 0.05}FeO{sub 3} prepared by hydrothermal method

Graphical abstract: Temperature variation of dielectric constant of Bi{sub 0.9}Ca{sub 0.05}Sm{sub 0.05}FeO{sub 3} at various frequencies as a function of temperature indicating anomalies at 420 and 540 K. - Highlights: • Substitution of Sm ions for Bi enhances the saturation magnetization of BiFeO{sub 3}. • XPS studies indicate the creation of oxygen vacancies upon Ca substitution. • Dielectric measurements show dielectric anomalies at high temperatures. • Raman spectra at high temperatures confirm the dielectric anomaly temperatures. - Abstract: Enhanced ferromagnetic properties and high temperature dielectric anomalies in the temperature range of 300–873 K in Bi{sub 0.9}Ca{sub 0.05}Sm{sub 0.05}FeO{sub 3} (BCSFO) prepared by hydrothermal method are reported. BiFeO{sub 3} is seen to crystallize in rhombohedrally distorted perovskite structure without any impurity phase. Substitution of small amount of Ca and Sm (Bi{sub 0.9}Ca{sub 0.05}Sm{sub 0.05}FeO{sub 3}) leads to increase in the lattice constant values and formation of small amount of secondary phase. Magnetization curve of pure BFO indicates very weak ferromagnetism combined with antiferromagnetic nature of the samples. Whereas, BCSFO sample shows very clear and enhanced ferromagnetic nature. Saturation magnetization and Neel’s temperature values are found to be 4.36 emu/g and 664 K, respectively. X-ray photoelectron spectroscopy indicates the creation of oxygenmore » vacancies upon Ca substitution in Bi site. Dielectric anomalies at 420 and 540 K were observed for Bi{sub 0.9}Ca{sub 0.05}Sm{sub 0.05}FeO{sub 3} from the temperature variation of dielectric constant and specific heat capacity measurements. Observation of dielectric anomalies in pure BiFeO{sub 3} sample reveals that the origin of dielectric peaks is purely from the primary phase. Raman spectroscopy study indicates a clear shift and broadening of A modes (between 100 and 200 cm{sup −1}) at the dielectric anomaly temperatures supporting the observed dielectric anomalies.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [1]
  1. Department of Materials Science and Engineering, KAIST (Korea Advanced Institute of Science and Technology), Daejeon 305-701 (Korea, Republic of)
  2. Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India)
  3. Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)
  4. School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 (Australia)
Publication Date:
OSTI Identifier:
22420796
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 62; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANTIFERROMAGNETISM; BISMUTH COMPOUNDS; CALCIUM COMPOUNDS; DIELECTRIC MATERIALS; FERRITES; FERROMAGNETISM; HYDROTHERMAL SYNTHESIS; LATTICE PARAMETERS; MAGNETIZATION; PERMITTIVITY; RAMAN SPECTRA; RAMAN SPECTROSCOPY; SAMARIUM COMPOUNDS; SAMARIUM IONS; SPECIFIC HEAT; TEMPERATURE DEPENDENCE; TRIGONAL LATTICES; VACANCIES; X-RAY PHOTOELECTRON SPECTROSCOPY