Journal of Materials Research

Articles

Dielectric properties characterization of La- and Dy-doped BiFeO3 thin films

Peter Kr. Petrova1 c1, Vaijayanti R. Palkara2, Alexander K Tagantseva3, Hsin-I Chiena4, K. Prashanthia5, Anna-Karin Axelssona6, S. Bhattacharyaa7 and Neil McN Alforda8

a1 Imperial College, London SW7 2AZ, United Kingdom

a2 Tata Institute of Fundamental Research, Mumbai 400005, India

a3 Ceramics Laboratory, Swiss Federal Institute of Technology (EPFL), Lausanne CH-1015, Switzerland

a4 London South Bank University, London SE1 0AA, United Kingdom

a5 Indian Institute of Technology Bombay, Mumbai 400076, India

a6 Imperial College, London SW7 2AZ, United Kingdom

a7 Tata Institute of Fundamental Research, Mumbai 400005, India

a8 Imperial College, London SW7 2AZ, United Kingdom

Abstract

The dielectric response of La- and Dy- doped BiFeO3 thin films at microwave frequencies (up to 12 GHz) has been monitored as a function of frequency, direct current (dc) electric field, and magnetic field in a temperature range from 25 to 300 °C. Both the real and imaginary parts of the response have been found to be non-monotonic (oscillating) functions of measuring frequency. These oscillations are not particularly sensitive to a dc electric field; however, they are substantially dampened by a magnetic field. The same effect has been observed when the volume of the characterized sample is increased. This phenomenon is attributed to the presence of a limited number of structural features with a resonance type response. The exact origin of these features is unknown at present. Leakage current investigations were performed on the whole set of films. The films were highly resistive with low leakage current, thereby giving us confidence in the microwave measurements. These typically revealed ‘N’-type I-V characteristics.

(Received January 3 2007)

(Accepted May 22 2007)

Key Words:

  • Dielectric properties;
  • Ferroelectricity;
  • Thin film

Correspondence:

c1 Address all correspondence to this author. e-mail: p.petrov@imperial.ac.uk

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