Tunable capacitors employing pyrochlore bismuth magnesium niobate thin films

Abstract

Tunable parallel plate capacitors employing Bi_1·5Mg_1·0Nb_1·5O₇ (BMN) thin films have been investigated. Dielectric measurements indicated that the capacitors exhibited low dielectric loss of 0·0028 and large dielectric constant of 111 at 1 MHz. The dielectric tunability of ∼14% was also obtained at a bias field of 1·3 MV cm⁻¹. In the frequency range from 10 kHz to 1 MHz, the dielectric constant and device quality factor were both observed slightly dropping as frequency increased, which may be associated with defects in the BMN films. Moreover, the BMN capacitors were found to have a very low leakage current density of 1·5×10⁻⁸ A cm⁻² at bias field of 80 kV cm⁻².

Keywords:

• Bismuth based pyrochlore
• Parallel plate capacitors
• Thin films
• Sielectric properties

Acknowledgements

The authors would like to thank the support from the National Natural Science Foundation of China (grant no. 50972024).