Superheating nature coupled with Mg‐doping effect of high thermal stable NdBa₂Cu₃O_7‐δ film

Abstract

NdBa2Cu3O7‐δ thin film deposited on a MgO substrate has been verified to remain solid above its peritectic melting temperature (Tp). Such a superheating nature is attributed to its low energy surface and epitaxial interface with substrate. Here, combining superheating nature with doping effect, we report a novel structure, Mg‐doped NdBa2Cu3O7‐δ film with YBa2Cu3O7‐δ buffer layer for the first time. Remarkably, this film presents a higher thermal stability level than heretofore possible when acting as a seed for preparing SmBa2Cu3O7‐δ bulks by melt growth, enduring a temperature of 1128°C, 43 K above its Tp for 1 hour. The utilization of such a high Tmax in melt growth is beneficial to the fabrication of large‐sized and high‐performance bulk in terms of effectively broadening the growth window and suppressing the heterogeneous nucleation. More importantly, some high thermal stability required technological applications, such as batch growth and failed bulk recycling, are likely to be realized by this novel Mg‐doped NdBa2Cu3O7‐δ film seed. Finally, we show how the observed metastable phase is linked to the distinctive film architecture.

A Novel Top Seeding Method for Reliable Growth of Single-Grain YBCO Bulk Superconductor with High Levitation Property above 26 N/cm2

“…Cai et al 12 reportedly used Nd-123/MgO thin films rather than the Nd-123 bulk crystals as the NdBCO film seeds for the growth of YBCO/Ag grains. Xu et al 13 15,16 reported a novel Mg-doped NdBCO film with a YBCO buffer layer that presented an even higher thermal stability than previously reported, as it endured a temperature of 1128 °C (43 K above its T p ) for 1 h.…”