Enhancement of YBCO Thin Film Thermal Stability under 1 ATM Oxygen Pressure by Intermediate Cu₂O Nanolayer

Abstract

The melting process of YBa(2)Cu(3)O(x) (YBCO or Y123) films under an oxygen atmosphere was observed in situ by means of high-temperature optical microscopy. The films were classified by pole figure measurement as c-axis oriented, with two different in-plane orientations (denoted as 0 and 45 degrees). In the 45 degrees-oriented films, electron diffraction and high-resolution transmission electron microscopy (HRTEM) detected an intermediate Cu(2)O nanolayer in the vicinity of the interface. The melting mode and the thermal stability of the YBCO thin films with different in-plane orientations were greatly influenced by oxygen partial pressure. Notably, the thermal stability of the 45 degrees-oriented YBCO films dramatically grew with increasing oxygen partial pressure. We attributed this effect to a change in the intermediate Cu(2)O nanolayer thermal stability. We conclude and suggest that the thermal stability of YBCO films can be significantly enhanced by inserting a Cu(2)O buffer nanolayer.

Peritectic melting of thin films, superheating and applications in growth of REBCO superconductors

“…(2) Different intrinsic structures Secondly, two kinds of c-axis oriented YBCO/MgO films with different four-symmetry in-plane orientations were in-situ investigated under 0.21 and 1 atm. oxygen partial pressures [47,48]. The films were denoted as film E (0°orientated grains) and film F (45°orientated grains), respectively, according to the pole figure results shown in Fig.…”

“…Optical micrographs showing the melting processes of film E and F in O 2 , respectively: (a and d) at the initial melting stage of about 1009°C; (b and e) at 1060°C; (c and f) at 1070°C[48].…”

“…A comparison of the surface morphology of YBCO films after the melting process: (a) film E, (b) film F[48].…”

“…The inset is the diffraction pattern of the 45°YBCO thin film, which determined the in-plane orientation of this film. (b) An enlarged image of the square area on figure (a), from which the Cu 2 O plane can be clearly observed[48].…”

Oxygen Plasma Effects on Zero Resistance Behavior of Yb,Er‐doped YBCO (123) Based Superconductors

“…[59][60][61] For mercury-containing compounds like Hg-1223, Hg-1201, and Hg-1212 for instance Morosin et al, [62] Fukuoka et al, [63] and Guillen-Vialett et al [64] could show the dependence of T c from annealing temperature and oxygen pressure. Besides influencing T c , oxygen treatment is considered to improve the stability of thin HTS layers [65] as well as rendering the critical current density. [66] It is known that via annealing of YBCO superconductors in pure oxygen at temperatures above 400 °C Oxygen is inserted into Cu(1)-O(1) chains.…”