Electric field control of the small-polaron hopping conduction in spatial confined Pr0.7(Ca0.6Sr0.4)0.3MnO3/PMN-PT heterostructure

The electric field dependent high-temperature small-polaron hopping conduction was investigated in patterned Pr0.7(Ca0.6Sr0.4)0.3MnO3 strips. The small-polaronic activation energy EA and the carrier localization were found to decrease with the reduction of the strip size. Meanwhile, a similar dependence on the strip size was also obtained for the calculated small-polaron coupling constants, which could be related to the strain relaxation in strips. These results indicate that the spatial confinement prefers to delocalize the carrier and reduce the electron-phonon interaction. Furthermore, opposite variation trends of EA under negative and positive electric field were found in the strips with small size, which could be attributed to the enhancement of polarization effect induced by the reduction of strip size.