Study of the oxygen depletion in the filmhyphen;substrate interface of superconducting YBa2Cu3O7minus;xfilms

摘要

Auger electron spectroscopy (AES) depth profiles were carried out onchyphen;axis oriented YBa2Cu3O7minus;xfilms growninsituonto SrTiO3(100) and polycrystalline yttriahyphen;stabilized zirconia substrates. These films were grown by onhyphen;axis singlehyphen;target dc planar magnetron sputtering, and they show zero resistance as high as 90.2 K and critical currents above 105A/cm2(77 K). The AES depth profiles reveal a clear oxygen loss at the interface. This oxygen deficiency corresponds to an atomic decrease from 7 to 6.6ndash;6.3 per unit cell, in good agreement with the tetragonal structure oxygen composition. This confirms the oxygenhyphen;deficient first stages of YBa2Cu3O7minus;xfilm growth on some usual cubic substrates, and that those first layers do not become fully oxidized after the oxygen intake on the cooling in O2atmosphere.