Multiferroic behavior and impedance spectroscopy of bilayered BiFeO{sub 3}/CoFe{sub 2}O{sub 4} thin films

Journal Article · Mon Jun 15 00:00:00 EDT 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3153955· OSTI ID:21352263

Jiagang, Wu; Wang, John ^[1]

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1. Department of Materials Science and Engineering, Faculty of Engineering, National University of Singapore, Singapore 117574 (Singapore)

Lead-free bilayered multiferroic thin films consisting of BiFeO{sub 3} (BFO) and CoFe{sub 2}O{sub 4} (CFO) layers with different thicknesses were grown on SrRuO{sub 3}-coated Pt/TiO{sub 2}/SiO{sub 2}/Si substrates by radio frequency sputtering. The effects of constituent layer thicknesses on the ferroelectric and magnetic behavior have been studied. The physical behaviors are shown to strongly depend on the thicknesses of the constituent layers. BFO (220 nm)/CFO (30 nm) bilayered thin film demonstrated much improved ferroelectric and ferromagnetic behavior (2P{sub r}=144.2 muC/cm{sup 2}, 2E{sub c}=778.0 kV/cm, M{sub s}=61.2 emu/cm{sup 3}, and H{sub c}=200.8 Oe) as compared to those of the single layer BFO thin film. The dielectric behavior and conductivity of BFO (220 nm)/CFO (30 nm) bilayered thin film were investigated as a function of both temperature (in the range of 294-534 K) and frequency (in the range of 10{sup -1}-10{sup 6} Hz), where an activation energy of approx1.11 eV for dielectric relaxation was demonstrated. From the conductivity behavior, an activation energies of approx0.98 eV was derived for dc conductivity are, implying that oxygen vacancies are involved in the conduction of the BFO (220 nm)/CFO (30 nm) bilayered film.

• OSTI ID: 21352263
• Journal Information: Journal of Applied Physics, Vol. 105, Issue 12; Other Information: DOI: 10.1063/1.3153955; (c) 2009 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
BISMUTH COMPOUNDS
COBALT OXIDES
DEPOSITION
ELECTRIC CONDUCTIVITY
FERROELECTRIC MATERIALS
FERROMAGNETIC MATERIALS
IMPEDANCE
LAYERS
OXYGEN
PLATINUM
RADIOWAVE RADIATION
SILICON OXIDES
SPECTROSCOPY
SPUTTERING
STRONTIUM COMPOUNDS
SUBSTRATES
THIN FILMS
TITANIUM OXIDES
VACANCIES
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
COBALT COMPOUNDS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIELECTRIC MATERIALS
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY
FILMS
MAGNETIC MATERIALS
MATERIALS
METALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLATINUM METALS
POINT DEFECTS
RADIATIONS
SILICON COMPOUNDS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS