Evolution of Morphology and Residual Stress of GdBa_2Cu_3O_(7-δ)/EuBa_2Cu_3O_(7-δ) Quasimultilayers

摘要

Aggregate thickness of 800 nm GdBa_2Cu_3O_(7-δ)/EuBa_2Cu_3O_(7-δ) multilayers with various layers are obtained by changing each layer thickness. The evolution of surface morphology, epitaxial texture, and residual stress of quasimultilayers GdBa_2Cu_3O_(7-δ)/EuBa_2Cu_3O_(7-δ) thin films deposited by pulsed laser deposition on Hastelloy substrates have been systematically investigated with scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction and Raman spectroscopy. SEM images of the YBCO films grown on Hastelloy substrates show smooth and density morphology. X-ray diffraction patterns indicated that superconducting multilayers varying from 2 to 32 layers have good epitaxial texture, but the relatively low temperature leads to weak crystallinity. Raman spectroscopy illustrates a significant change of residual stress as films layers increase from 8 to 16 layers. With an optimization for crystallization processes, better microstructure and superconducting performance of quasimultilayers are expected.