  Applying an external pressure to indirectly electron-doped 122-type
(Ba1-xLax)Fe2As2 epitaxial films enhances the superconducting critical
temperature (Tc) up to 30.3 K. Different from the other family compounds, the
Tc is enhanced not only in the under-doped region but also in the optimally
doped and over-doped regions. Narrowing of the superconducting transition width
and an increase in the carrier density take place simultaneously in the whole
doping region, except at the heavily over-doped limit. This characteristic is
unique to and observed only in (Ba1-xLax)Fe2As2, in which the La doping is
stabilized via non-equilibrium growth of the vapor phase epitaxy, among the
122-type iron-based superconductors, AFe2As2 (A = Ba, Sr, and Ca).
