${\rm SmBa}_{2}{\rm Cu}_{3}{\rm O}_{7-\delta}$ Coated Conductors on the IBAD-MgO Substrate Fabricated by the Ex-situ Conversion Process

We investigated the
ex-situ
conversion process of amorphous precursor films for SmBa
₂
Cu
₃
O
_7-delta
(SmBCO) coated conductors (CC). Amorphous precursor films were first deposited on the LaMnO
₃
/homoepi-MgO/ IBAD-MgO/Y
₂
O
₃
/Al
₂
O
₃
/Hastelloy substrate by e-beam co-evaporation and subsequently crystallized to the superconducting phase at various post-annealing temperatures in two different reduced oxygen pressures. In 100 ppm of O
₂
in Ar,
c
-axis oriented SmBCO grains with minor a-axis oriented grains were grown at 825degC whereas polycrystalline SmBCO film with some
a
-axis oriented grains was formed at 800degC. In the temperature region of 825 ~ 850degC, protruded spots were observed on the sample surface. In 6 ppm of O
₂
in Ar, SmBCO film composed of
a
-axis oriented SmBCO grains with partial c-axis oriented grains were obtained at 700degC but other phases were formed above 725degC. The SmBCO sample grown at 700degC exhibited
Tc

_,zero
value of 90.2 K. However, its
Jc
value at 77 K was negligibly small due to the formation of
a
-axis oriented grains.