Transport Critical Current Density of $\hbox{Sr}_{0.6}\hbox{K}_{0.4}\hbox{Fe}_{2}\hbox{As}_{2}\hbox{/}\hbox{Ag}$ Superconducting Tapes Processed by Flat Rolling and Uniaxial Pressing

Ag-sheathed Sr
_0.6
K
_0.4
Fe
₂
As
₂
superconducting tapes with various thicknesses were produced by flat rolling and cold uniaxial pressing based on an ex-situ powder-in-tube method. The transport critical current density (J
_c
) for both rolled and pressed tapes was found to increase with the decrease of tape thickness. Compared with flat rolling, cold pressing can further enhance the transport Jc of Sr
_0.6
K
_0.4
Fe
₂
As
₂
tapes. A transport J
_c
as high as 4.8 × 10
⁴
A/cm
²
at 4.2 K and 10 T was achieved by pressing Sr
_0.6
K
_0.4
Fe
₂
As
₂
tapes at about 1.0 GPa. This superior transport J
_c
in the pressed tapes can be ascribed to improved mass density and grain texture of Sr
_0.6
K
_0.4
Fe
₂
As
₂
superconducting cores.