Superheating of solids, an unconventional phenomenon in nature,
can be achieved by suppressing the heterogeneous nucleation of
melt at defect sites, such as free surfaces and internal grain boundaries.
In recent years, experimental evidences have clearly proved
that the YBCO (Y123) thin film with a free surface possesses a
superheating capacity, which is mainly attributed to the film/substrate
structures, distinctively consisting with low-energy surface
and semi-coherent interface. Like most functional oxides, YBCO
(denoted as a phase) is characterized by a peritectic melting:
a?b + liq. Its superheating behavior certainly relates to this
peritectic reaction. Furthermore, REBCO (RE123, RE: rare earth
elements) thin films with high thermal stability have been successfully
employed as seed materials in inducing the growth of REBCO
materials, such as thick film, single crystal and single domain bulk.
Therefore, this superheating property of thin films is of great
importance in both scientific study and practical application. In
this paper, the up-to-date researches covering on the superheating
phenomenon of the a phase film, its mechanism and applications
in growth of REBCO superconductors are reviewed, which is
supposed to be valid for more thin films of functional oxides that
have the same nature as the YBCO film/substrate.