Modulation of charge carrier dynamics and hence electrical conductivity of
solids by photoexcitation has been a rich field of research with numerous
applications. Similarly, electric and magnetic field assisted enhancement of
conductivity are of fundamental importance and technological use. Hole doped
manganites of the type (A1−x​Bx​)MnO3​, where A and B are rare and
alkaline earth metals respectively have the distinction of showing all three
effects. Here we establish the complementarity of the electric, magnetic and
photon fields in driving an insulator-metal transition in epitaxial thin films
of La0.175​Pr0.45​Ca0.375​MnO3​ whose electrical ground state
is insulating. Both pulsed and CW lasers cause a giant photon flux dependent
enhancement of conductivity. It is further observed that electric and magnetic
fields trigger the persistent enhancement of conductivity whose magnitude can
be accentuated by application of these fields in parallel.Comment: 17 pages 6 figure