β Growth kinetics from α peritectic melting of oxide films

Melting behavior and superheating capacity of REBa2Cu3Oy films with nano‐layer buffered structures

“…It appears that the melting growth of the Y123 nano‐film was suppressed owing to two factors. One is the poor wettability of the BCO liquid with both Nd123 film and MgO substrate . And the other is the low interface energy at Nd123/Y123 and Y123/MgO border.…”

“…Nowadays, deep investigation on the superheating mechanism, searching novel structures possessing the high superheating capability, and realizing its practical application attract great attention in the scientific world . In recent years, experimental evidences have clearly proved that the c ‐axis oriented RE123 (REBa 2 Cu 3 O y , RE = Nd, Sm and Y) films on the MgO substrate (shortly, RE123/MgO), as a quasi‐2D structure possesses a superheating capacity, i.e., the RE123 film may remain in its metastable solid phase above its peritectic melting temperature over several tens degrees . Like most functional oxide materials, RE123 features anisotropic surface energy in the crystalline plane (equivalent to anisotropic melting temperature) and the a‐b plane is characterized by the low surface energy, which is the intrinsic reason why this quasi‐2D nanocrystalline film does not easily melt.…”

“…Furthermore, Y123 buffered Nd123 films (Nd123/Y123/MgO), was remarkably reported to have a stronger superheating effect. Because of their superheating nature, the RE123 films have been widely used as the seed materials in many processes, such as liquid phase epitaxy (LPE), top‐seeded solution growth (TSSG) and top seeded melt‐growth (TSMG) . This induced intermediate layer with a thickness of several tens nanometer, has a profound effect on the 2D‐Nd123 film, suppressing misfit‐caused defects at its interface, improving the film crystallinity, reducing its interface energy, and eventually increasing the nucleation barrier for its melting.…”

“…Moreover, Yan et al pointed out that the Nd123 thin film has low thermal stability than the Y123 film due to its higher growth rate of Nd 4 Ba 2 Cu 2 O 10 than that of Y 2 BaCuO 5 , which are derived from the RE123 decomposition. Finally, Chen et al proved that the superheating phenomenon universally exists in all Y123 films deposited on various substrates like MgO, STO, LAO and the highest level of superheating over a 100K has been astonishingly observed on the Y123/LAO film. All above mentioned work is helpful to clarify and understand the nature of RE123 film superheating phenomenon.…”