Temperature dependence of the electrical and electromechanical properties of PZT thin films

The electrical and electromechanical properties of PZT thin films are extensively investigated. The PZT thin films were prepared by chemical solution deposition. For thick film deposition, the solutions with a relatively high metal concentration of 15-25 wt% are used. Film thickness is controlled up to 2.0 mum by repeating the spin coating, and all the 0.4, 1.0 and 2.0 mum-thick films exhibited well-saturated polarization hysteresis loops, with their differences being trivial. With an increase of film thickness, electric field-induced strain increased remarkably; 2.0 mum-thick film exhibited strains corresponding to 280 pm/V. The reason for the electromechanical properties' dependence on film thickness are examined by means of phenomenological calculation and by analyzing the temperature dependence of dielectic and ferroelectric properties of the films down to 20 K.