Colossal pressure-induced negative resistance change in La2/3Ca1/3MnO3 thin films

Ca1/3MnO3 thin films as a function of temperature from 4 to 300 K are studied. The application of external pressure increases the temperature of the metal–insulator transition (TMI). For a film showing TMI at about 177 K, a colossal change in resisitivity (R(0)-R(p))/R(p) qualitatively comparable to the magnetoresistance (R(0)-R(B))/R(B) around the transition temperature, is observed. However, this change for the film with high TMI (267 K) is smaller by a factor of about 100. The increase of TMI with pressure is intimately associated with the pressure-induced contraction and alignment of Mn-O-Mn bonds and the possible enhancement of the double-exchange interaction with pressure.