Electroresistance of Electrically Nonhomogeneous La$\text{}_{0.67}$Ca$\text{}_{0.33}$MnO$\text{}_{3}$/MgO Thin Films

Current and electrical field-induced electroresistive effects were investigated for La$\text{}_{0.67}$Ca$\text{}_{0.33}$MnO$\text{}_{3}$/MgO thin films demonstrating nanosized electrical inhomogeneities. Two different models based on enhanced conductivity of intergrain boundaries by injecting spin-polarized carriers from ferromagnetic grains and electrical field-enhanced hopping of carriers in high resistance intergrain media were carried out to explain nonlinear electrical properties of the films.