  Tremendous efforts towards improvement in the critical current density (Jc)
of iron based superconductors (FeSCs), especially at relatively low
temperatures and magnetic fields, have been made so far through different
methods, resulting in real progress. Jc at high temperatures in high fields
still needs to be further improved, however, in order to meet the requirements
of practical applications. Here, we demonstrate a simple approach to achieve
this. Hydrostatic pressure can significantly enhance Jc in NaFe0.97Co0.03As
single crystals by at least tenfold at low field and more than a hundredfold at
high fields. Significant enhancement in the in-field performance of
NaFe0.97Co0.03As single crystal in terms of pinning force density (Fp) is found
at high pressures. At high fields, the Fp is over 20 and 80 times higher than
under ambient pressure at12K and 14K, respectively, at P=1GPa. We believe that
the Co-doped NaFeAs compounds are very exciting and deserve to be more
intensively investigated. Finally, it is worthwhile to say that by using
hydrostatic pressure, we can achieve more milestones in terms of high Jc values
in different superconductors.
