Peculiarities of crystallization of thin ferroelectric films of lead zirconate titanate

The thermodynamics of processes involved in the growth and annealing of ferroelectric films of lead zirconate titanate Pb(Ti,Zr)O3 (PZT) has been studied using the method of synchronous thermal analysis (STA). Thin PZT films were grown by the RF magnetron sputtering and then annealed in air or in an inert gas (argon) at atmospheric pressure and various temperatures within 20–600°C. It was found that the annealing in an oxygen-containing medium (air) is accompanied by changes in the enthalpy and mass of the system, which is due to the interaction with oxygen, while the heat treatment in an inert medium did not lead to any changes in the PZT film. It is established that the observed changes are related to the conversion of lead monoxide into orthoplumbate in the PZT film volume. STA experiments demonstrate that this transformation leads to a significant change in the structure of the ferroelectric film. Based on these data, a mechanism is proposed that accounts for the structural changes involved in the annealing of PZT films.