  Pressure is well known to significantly raise the superconducting transition
temperature, Tc, in both iron pnictides and cuprate based superconductors.
Little work has been done, however, on how pressure can affect the flux pinning
and critical current density in the Fe-based superconductors. Here, we propose
to use hydrostatic pressure to significantly enhance flux pinning and Tc in
polycrystalline pnictide bulks. We have chosen Sr4V2O6Fe2As2 polycrystalline
samples as a case study. We demonstrate that the hydrostatic pressure up to 1.2
GPa can not only significantly increase Tc from 15 K (underdoped) to 22 K, but
also significantly enhance the irreversibility field, Hirr, by a factor of 4 at
7 K, as well as the critical current density, Jc, by up to 30 times at both low
and high fields. It was found that pressure can induce more point defects,
which are mainly responsible for the Jc enhancement. In addition, we found that
the transformation from surface pinning to point pinning induced by pressure
was accompanied by a reduction of anisotropy at high temperatures. Our findings
provide an effective method to significantly enhance Tc, Jc, Hirr, and the
upper critical field, Hc2, for other families of Fe-based superconductors in
the forms of wires/tapes, films, and single crystal and polycrystalline bulks.
