Complementarity of perturbations driving insulator-to-metal transition in a charge-ordered manganite

Condensed Matter - Low Dimensional Systems Laboratory, Department of Physics, Indian Institute of Technology Kanpur - Kanpur, 208016, India

Corresponding author: rcb@iitk.ac.in

Received: 5 August 2007
Accepted: 29 October 2007

Abstract

Modulation of charge carrier dynamics and hence electrical conductivity of solids by photo-excitation 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 (AB_x)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 La_0.175Pr_0.45Ca_0.375MnO₃ 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.