Dielectric dynamics of epitaxial BiFeO3 thin films

Abstract

We report the detailed study on the low temperature dielectric dynamics of the epitaxial BiFeO3 thin films grown on Nb-doped SrTiO3 substrate. The results indicate that the contributions from the thin film dominate the dielectric response, although it comes from both the thin film and the electrode interface. Furthermore, the origins of the low temperature dielectric anomalies are investigated with electric circuit fittings. A possible phase transition at 210 K is revealed from analysis with dielectric loss tangent. The dielectric constants obtained from the constant phase elements (CPEs) are more than 400 even at low temperatures. Finally, the physical significances of the CPE model are discussed

Conduction mechanism in epitaxial BiFe0.95Mn0.05O3 thin film

“…The room temperature multiferroic nature of the BFO allows indeed broad range of applications in various domains such as for example electronic, optoelectronics, energy storage and information storage [1][2][3][4]. BFO and BFO based solid solutions scientific and technological importance are emphasized by the many number of articles published (see [1][2][3][4][5][6][7][8][9][10][11][12] and references therein). BFO bulk adopts rhombohedral structure (R3c space group) and a pseudocubic lattice parameter of about 3.96 Å.…”

Fabrication/characterization of multiferroic LuFe2O4 and BiFeO3 and their dielectric properties

“…The loss tangent can be smaller than 1 at room temperature with frequency higher than 1kHz. Small dielectric loss tangent also indicates that the sample used is insulating (110). Similar slop changes with this temperature range have been reported in both single crystalline and polycrystalline BFO.…”

“…The inductance comes from the contact leads. The capacitance of the experimental setup is below 5×10 -14 F which is much smaller than the minimum measured value in our results (110).…”

“…The measured imaginary part of the impedance shows even smaller difference with the CPE1-G1. (110) The impedance data can be transferred to many other forms, for example, the dielectric-loss tangent or the Module. The purpose of this is usually to show different components in a more straightforward way.…”

“…This further indicates that the dielectric anomalies cannot be related to the phase transition directly. The equivalent circuit based curve fitting is necessary to eliminate the extrinsic effects (110). Physical significance of the CPE parametersThe CPE have been widely used in the IS fittings in many different systems to get a better fit of the non-Debye like dielectric responses.…”