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Title: Structural, magnetic, and dielectric studies of the Aurivillius compounds SrBi{sub 5}Ti{sub 4}MnO{sub 18} and SrBi{sub 5}Ti{sub 4}Mn{sub 0.5}Co{sub 0.5}O{sub 18}

We have successfully synthesized the Aurivillius compounds SrBi{sub 5}Ti{sub 4}MnO{sub 18} and SrBi{sub 5}Ti{sub 4}Mn{sub 0.5}Co{sub 0.5}O{sub 18} using a modified Pechini method. Both samples have an orthorhombic structure with the space group B2cb. The valence state of Mn is suggested to be +3 and the doped Co ions exist in the form of Co{sup 2+} and Co{sup 3+} based on the results of x-ray photoelectron spectroscopy. The sample SrBi{sub 5}Ti{sub 4}MnO{sub 18} exhibits a dominant paramagnetic state with the existence of superparamagnetic state as evidenced by the electron paramagnetic resonance results, whereas SrBi{sub 5}Ti{sub 4}Mn{sub 0.5}Co{sub 0.5}O{sub 18} undergoes a ferrimagnetic transition at 161 K originating from the antiferromagnetic coupling of Co-based and Mn-based sublattices, and a ferromagnetic transition at 45 K arising from the Mn{sup 3+}-O-Co{sup 3+} (low spin) interaction. The sample SrBi{sub 5}Ti{sub 4}Mn{sub 0.5}Co{sub 0.5}O{sub 18} exhibits two dielectric anomalies. One corresponds to a relaxor-like dielectric relaxation which follows the Vogel-Fulcher function and the other dielectric relaxation obeys the Arrhenius law arising from the collective motion of oxygen vacancies. In addition, the sample SrBi{sub 5}Ti{sub 4}Mn{sub 0.5}Co{sub 0.5}O{sub 18} exhibits a magnetodielectric effect caused by the Maxwell-Wagner effect because of the conductivity of the sample. This is demonstratedmore » by the fact that the activation energy in dielectric loss process is close to that for dc conductivity and the magnetodielectric effect is sensitive to the measured frequency.« less
Authors:
; ; ; ; ; ;  [1] ;  [1] ;  [2] ;  [1] ;  [2] ;  [2]
  1. Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22412822
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANTIFERROMAGNETISM; BISMUTH COMPOUNDS; COBALT COMPOUNDS; COBALT IONS; COUPLING; DIELECTRIC MATERIALS; DOPED MATERIALS; ELECTRON SPIN RESONANCE; MANGANATES; MANGANESE IONS; ORTHORHOMBIC LATTICES; PARAMAGNETISM; STRONTIUM COMPOUNDS; SUPERPARAMAGNETISM; TITANIUM COMPOUNDS; VACANCIES; X-RAY PHOTOELECTRON SPECTROSCOPY