Dielectric relaxation measurements on Pb1x Lax(Zr0.65Ti0.35)1x/4O3 with x = 0.09 (PLZT 9/65/35) thin films are presented. These films have been grown by pulsed laser deposition (PLD) assisted by radio frequency (RF) discharge in oxygen which allows to increase the plasma reactivity and to reduce the oxygen vacancies in films and at the film-bottom electrode interface. The small signal dielectric constant and loss have been measured in the frequency range 100 Hz1 MHz while temperature was varied between 300 K and 570 K. Dielectric permittivity vs. temperature variation was typical of relaxor ferroelectrics, with a broad peak that shifted towards lower temperature for lower driving signal frequency. The temperature of the dielectric maximum was close to that obtained in bulk (about 340 K) but the permittivity value was much lower. This was attributed to two causes: (i) the presence of small quantities of pyrochlore phase; (ii) a low permittivity interface layer. The room temperature permittivity showed a linear decrease with the logarithm of driving field frequency, indicating a dominating contribution from domain-wall pinning processes below transition temperature.
Dielectric spectroscopy measurement of relaxor ferroelectric PLZT 9/65/35 thin films obtained by RF assisted PLD
Craciun F;Verardi P;
2004
Abstract
Dielectric relaxation measurements on Pb1x Lax(Zr0.65Ti0.35)1x/4O3 with x = 0.09 (PLZT 9/65/35) thin films are presented. These films have been grown by pulsed laser deposition (PLD) assisted by radio frequency (RF) discharge in oxygen which allows to increase the plasma reactivity and to reduce the oxygen vacancies in films and at the film-bottom electrode interface. The small signal dielectric constant and loss have been measured in the frequency range 100 Hz1 MHz while temperature was varied between 300 K and 570 K. Dielectric permittivity vs. temperature variation was typical of relaxor ferroelectrics, with a broad peak that shifted towards lower temperature for lower driving signal frequency. The temperature of the dielectric maximum was close to that obtained in bulk (about 340 K) but the permittivity value was much lower. This was attributed to two causes: (i) the presence of small quantities of pyrochlore phase; (ii) a low permittivity interface layer. The room temperature permittivity showed a linear decrease with the logarithm of driving field frequency, indicating a dominating contribution from domain-wall pinning processes below transition temperature.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
