Effect of temperature and film thickness on microstructure and residual stress for YbBCO-coated conductors

• Published in: Journal of alloys and compounds Vol. 471; no. 1; pp. 282 - 290
• Main Authors: Arda, L., Ataoglu, S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 05-03-2009; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Elasticity; Exact sciences and technology; High- Tc superconductors; High-tc films; Microstructure; Physics; Sol–gel processes; Superconducting films and low-dimensional structures; Superconductivity; Thermal analysis; YbBCO; Elasticity; High- T c superconductors; Sol–gel processes; Thermal analysis; Microstructure; YbBCO; Buffer layer; Atomic force microscopy; Annealing; Surface morphology; Residual stresses; XRD; Texture; Thickness; Superconducting films; High-Tc superconductors; Environmental scanning electron microscopy; Coated conductor; Sol-gel processes; Gadolinium Holmium Oxides Mixed; Dip coating; Sol-gel process; Barium Copper Yttrium Oxides Mixed; Pole figures
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2008.03.091

The rare-earth mixed oxide (Gd
1−
x
Ho
x
)
2O
3 and the superconductor YbBa
2Cu
3O
7−
x
were prepared by sol–gel synthesis using metal–organic precursors. Textured Gd
1.802Ho
0.198O
3 buffer layers were grown on biaxially textured Ni (1
0
0) substrates. YbBa
2Cu
3O
7−
x
layers were epitaxially grown on the Gd
1.802Ho
0.198O
3-coated Ni substrates using the reel-to-reel sol–gel dip coating system. Different thicknesses of superconducting layers, annealed at various temperatures, were tried to observe the effects of thickness and temperature on residual stress and microstructure properties. Residual stress in the YbBCO/Gd
1.802Ho
0.198O
3/Ni was calculated analytically. The results showed that variation of residual stress along the thickness of structure (Ni substrate, buffer layer and YbBCO film) was constant. We also observed that the Ni substrate is under tension while buffer layer was under compression in the case of without YbBCO layer. However the residual stress was under compression in the case of YbBCO in all layers. The surface morphologies and microstructure of all samples were characterized by environmental scanning electron microscope (ESEM), atomic force microscope (AFM) and X-ray diffraction (XRD). The pole figure texture analyses of Ni substrate, Gd
1.802Ho
0.198O
3 buffer layers and YbBCO film have shown a single cube-on-cube textured structure.