Electronic transport properties of charge-ordered Bi0.4Ca0.6MnO3 film

The electronic transport properties of charge-ordered Bi0.4Ca0.6MnO3 films grown on a (110) SrTiO3 substrate are experimentally studied. Special attention has been paid to the Hall effect around the charge-ordering (CO) transition. The charge carriers are found to be electron-like, and the carrier density n exhibits a significant change upon the CO transition: it is nearly constant above the transition temperature T-co similar to 0.36 electrons/Mn, and reduces with decrease of the temperature below T-co following the formula n proportional to exp(-E-H/k(B)T), with an activation energy E-H of similar to 0.13 eV. In contrast, no obvious signatures of thermal activation for Hall mobility were observed. Meanwhile, it is revealed that magnetic field affects the resistivity by enhancing the carrier mobility of the film in the course of the CO transition.