Effect of oxygen annealing on the multiferroic properties of Ca{sup 2+} doped BiFeO{sub 3} nanoceramics
- Department of Physics, Indian Institute of Technology, Kharagpur 721302 (India)
- Department of Physics, Rajiv Gandhi University of Knowledge Technologies, RK Valley 516329 (India)
The high leakage current in divalent ion doped BiFeO{sub 3} systems is limiting their large scale application. It is clearly shown that the methodology of oxygen annealing will prove to be an effective procedure for suppressing the detrimental consequences that originate from the oxygen vacancies. The samples annealed under oxygen also show different particle morphologies and packing density that can help in tuning the relevant physical properties, viz., magnetic, ferroelectric, and magnetoelectric. The difference in magnetic behaviour in samples annealed in air and oxygen can be explained in terms of the modification in the Fe-O-Fe bonds, domain wall pinning centres, and crystal anisotropy. Another important observation is the stabilization of a dielectric anomaly near the magnetic transition temperature. This observation can make this multiferroic system very interesting for application in sensors where the change in the magnetic parameters can be observed by monitoring the electrical parameters. Detailed analysis of the dielectric and impedance curves indicate towards the presence of non-Debye type processes in samples obtained by annealing in air or oxygen. From the calculated activation energy values, the vacancy related relaxation mechanism is predominant in air annealed samples, while the oxygen annealed samples show the presence of two type of relaxation processes, viz., electron hopping mechanism stabilizes at low temperature while, at higher temperatures, the process associated with the diffusion of doubly ionized oxygen ions predominates. The ac-conductivity data suggests that the correlated barrier tunnelling mechanism, where single electron or two electrons hopping through neighbouring lattice sites leads to ac-conduction.
- OSTI ID:
- 22399163
- Journal Information:
- Journal of Applied Physics, Vol. 116, Issue 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACTIVATION ENERGY
ANNEALING
BISMUTH COMPOUNDS
CALCIUM IONS
CRYSTALS
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRONS
FERROELECTRIC MATERIALS
IMPEDANCE
IRON OXIDES
LEAKAGE CURRENT
MAGNETIC PROPERTIES
OXYGEN
OXYGEN IONS
RELAXATION
TRANSITION TEMPERATURE
TUNNEL EFFECT
VACANCIES