TEM observations of Gd 2Zr 2O 7 films formed by the ion-beam-assisted deposition method on an Ni-based alloy

Abstract

Gd 2Zr 2O 7 films were formed by the ion-beam-assisted deposition (IBAD) method on an Ni-based alloy. Cross-sectional and plan-view specimens of the films were prepared for transmission electron microscopy investigation and microstructural characterization. The thicknesses of the Gd 2Zr 2O 7 films were less than 1.3 μm. During initial formation of the films, tiny grains nucleated close to the Ni-based alloy, followed by gradual formation of a columnar texture composed of fine 〈0 0 1〉 aligned grains perpendicular to the Ni-based alloy interface. However, dark-field image taken under g → =(4 4 0) indicated that the in-plane mosaic spread of the columnar texture did not improve as much as the [0 0 1] tilt angle. However, examination of the Gd 2Zr 2O 7 film surfaces revealed that the interfaces between columns were not well defined. Furthermore, a CeO 2 film deposited on a 1.3 μm thick Gd 2Zr 2O 7 film by the pulsed laser deposition (PLD) method contained less in-plane mosaic spread than the Gd 2Zr 2O 7 film alone. PLD-CeO 2/IBAD-Gd 2Zr 2O 7 films are therefore considered promising candidates for use as buffer layers in superconductor tapes.