Observation of Interface Stress in Barrier/Y-Ba-Cu-O Structure by Laser Raman Scattering Spectroscopy

Stress at the interface between thin Y-Ba-Cu-O film and various insulating materials deposited on Y-Ba-Cu-O was investigated by laser Raman scattering spectroscopy. The shift of the phonon mode at 500 cm-1, which is the stretching vibration associated with O-Cu-O bonding parallel to the c-axis, indicates the existence of stress in the interface region of Y-Ba-Cu-O. As the penetration depth of the 514.5 nm incident light was estimated to be less than 40 nm, this method was found to be effective for the characterization of the junction interface.