High Critical Current Density in Cu-Sheathed SmFeAsO1-xFx Superconducting Tapes by Low-Temperature Hot-Pressing

Cu-sheathed SmFeAsO
_1-x
F
_x
tapes were fabricated by the
ex situ
powder-in-tube method. A series of low-temperature (400 °C) hot-pressing process and ordinary sintering process was applied on the tapes, respectively. A transport critical current density
$(J_{c})$
value of
$2.37 \times 10^{4}\ \text{A cm}^{-2}$
(at 4.2 K and self-field) was achieved in the Cu-sheathed SmFeAsO
_1-x
F
_x
hot-pressed tapes. This is the first time that a large transport
$J_{c}$
is obtained in Cu-sheathed 1111-type wires. The scanning electron microscopy also revealed that the low-temperature hot-pressing technique is effective in preventing the reaction layer between Cu-sheath and superconducting core.