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Structural, spectroscopic, magnetic and electrical characterization of Ca-doped polycrystalline bismuth ferrite, Bi1?xCaxFeO3?x/2 (x ? 0.1)

DOI: 10.1088/0953-8984/24/4/045905 DOI Help

Authors: Kripasindhu Sardar (University of Warwick) , Jiawang Hong (Rutgers, State University of New Jersey) , Gustau Catalan (ICREA and Centre d'Investigacions en Nanociencia'i Nanotecnologia (CIN2)) , P. K. Biswas (University of Warwick) , Martin Lees (University of Warwick) , Richard Walton (University of Warwick) , James F. Scott (University of Cambridge) , Simon Redfern (University of Cambridge)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Physics: Condensed Matter , VOL 24 (4)

State: Published (Approved)
Published: January 2012

Abstract: The crystal structure and physical properties of multiferroic polycrystalline Ca2+-doped BiFeO3 samples have been investigated. The present experimental investigation suggests that Bi1?xCaxFeO3?x/2 (x ? 0.1) can be considered as a solid solution between BiFeO3 and CaFeO2.5. The oxidation state of Fe in these materials is + 3 and charge balance occurs through the creation of oxygen vacancies. For each composition, two structural phase transitions are revealed as anomalies in the variable-temperature in situ x-ray diffraction data which is consistent with the well-established high-temperature structural transformation in pure BiFeO3. All compositions studied show antiferromagnetic behaviour along with a ferromagnetic component that increases with Ca2+ doping. The resistivities of the Bi1?xCaxFeO3?x/2 samples at room temperature are of the order of 109 ? cm and decrease with increasing Ca2+ content. Arrhenius plots of the resistivity show two distinct linear regions with activation energies in the range of 0.4–0.7 and 0.03–0.16 eV. A correlation has been established between the critical temperatures associated with the structural phase transitions and the multiferroic properties. A composition of x = 0.085 is predicted to show maximum magneto-electric coupling.

Subject Areas: Physics

Instruments: B18-Core EXAFS

Added On: 10/01/2012 11:01

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