Effect of iron doping on the physical properties of europium manganites

▸ Single-phase polycrystalline perovskites Eu0.65Sr0.35FexMn1−xO3 (x=0.1 and 0.5) were synthesized by a solid state reaction technique. ▸ The microstructure study showed that the grain size decreases with increasing the iron concentration. ▸ The electrical resistivity decreased with increasing tempe...

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Bibliographic Details
Published in:Journal of alloys and compounds 2012-07, Vol.530, p.116-120
Main Authors: Abdel-Latif, I.A., Saleh, S.A.
Format: Article
Language:English
Subjects:
Alloys
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Dielectric constant
Dielectric constants
Doping
Electrical resistivity
Europium ferrimanganites
Exact sciences and technology
Field emission
Iron
Magnetic properties and materials
Magnetotransport phenomena, materials for magnetotransport
Manganites
Microstructure
Physics
Raman spectroscopy
Scanning electron microscopy
Semiconductors
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Summary:▸ Single-phase polycrystalline perovskites Eu0.65Sr0.35FexMn1−xO3 (x=0.1 and 0.5) were synthesized by a solid state reaction technique. ▸ The microstructure study showed that the grain size decreases with increasing the iron concentration. ▸ The electrical resistivity decreased with increasing temperature and the conduction mechanism is thermally activated. ▸ The frequency dependence of the dielectric constant in these compounds indicates that space charge polarization contributes significantly to their observed dielectric parameters. ▸ An increase in the dielectric constants with increasing the iron content is observed and a decrease with changing the measuring frequency at room temperature. Polycrystalline samples of Eu0.65Sr0.35FexMn1−xO3 (x=0.1 and 0.5) were prepared by a solid state reaction technique. Preliminary microstructure and crystal structure of the compound at room temperature were studied using field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) technique, respectively. It is found that with Fe doping, the grain size decreases, where the compound crystallizes in a single-phase orthorhombic structure. Both samples show three active Raman vibrational modes around 210, 488 and 610cm−1. The substitution of Fe at the Mn site results in a slightly change in band positions of Raman spectra. The temperature variation of resistivity shows that these compounds have semiconductor behavior with activation energy 0.152eV for x=0.1 increases to the value 0.535eV for x=0.5. The frequency dependence of dielectric constant in these materials indicates that space charge polarization contributes significantly to their observed dielectric parameters.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2012.03.079