Improvement of Electromechanical Coupling Coefficient of Piezoelectric LiNbO3 by Doping Praseodymium

The c-axis oriented LiNbO
3
(LN) and praseodymium (Pr) doped LN films were fabricated by RF magnetron sputtering. The epitaxial growth of the films was confirmed by the measurement of XRD pole figure. Their electromechanical coupling coefficient
$k_{t}^{2}$
were estimated by the conversion loss method. The minimum conversion loss for the Pr-LN film was measured to be 14 dB at 1.5 GHz along the film thickness direction. The
$k_{t}^{2}$
value of Pr - LN film was improved to 2.2% from 0.8% of epitaxial LN film, demonstrating that doping Pr into LN film is a good way of improving the electromechanical coupling coefficient of piezoelectric LN film.