Influence of reducing atmosphere on the defect chemistry of lead lanthanum zirconate titanate (8/65/35)

The defect structure of lanthanum-modified lead-zirconate-titanate (PLZT) is altered by annealing at 700 °C in different reducing atmospheres and studied by conductivity measurements, different spectroscopic techniques and determination of the thermally stimulated depolarization current (TSDC). It is found that annealing at an oxygen partial pressure of pO2<10−16pO2<10−16 bar leads to the formation of oxygen vacancies VO
•  
• or VO×. If hydrogen is present in the reducing atmosphere, it can be incorporated as either HO
• or OHO
• . The defects can be evidenced in both the IR and UV/VIS absorption spectra. Additionally, high levels of reduction cause a shift in the Fermi level, leading to the population of intrinsic Fe impurities, which can possibly be utilized as photorefractive centers.

► Polycrystalline PLZT ceramics have been annealed in different reducing atmospheres.
► Oxygen vacancies are the main type of defects created.
► Annealing in H-containing atmospheres leads to additional incorporation of hydrogen.
► Incorporation can be in the form of hydroxide or hydride defects.
► Defects are evidenced in electrical conductivity and optical absorption properties.