Microstructures of BaZrO₃-doped ErBa₂Cu₃O_y films fabricated by different BaZrO₃ supply

ErBa₂Cu₃O_y films including BaZrO₃ are deposited using three types of targets by PLD to realize the self-oriented growth of BaZrO₃ nanorods. Microstructures of the obtained films are observed using a transmission electron microscope (TEM). On the basis of the cross-sectional TEM images, the growth mechanism of the BaZrO₃ nanorods is discussed. When about a half of BaZrO₃-monolayer is added, it is found that the BaZrO₃ is not widely segregated to BaZrO₃ region and no BaZrO₃ region on the ErBa₂Cu₃O_y surface but the BaZrO₃ is homogeneously distributed with approximately 10 nm periods on the ErBa₂Cu₃O_y surface. As a result, the crystal stress due to the differences of crystal length between the ErBa₂Cu₃O_y and BaZrO₃ are introduced for every 10 nm to the films. This behavior is probably the origin of the self-oriented growth of BaZrO₃ nanorods.