Electrical transport in manganite granular systems

摘要: A systematic investigation of magnetic and transport properties is carried out for ${\mathrm{La}}_{2/3}{\mathrm{Ca}}_{1/3}{\mathrm{MnO}}_{3}$ granular system. Based on the magnetization measurement, it argued that oscillatory indirect exchange coupling via boundary material with thickness s sandwiched between neighboring grains exists in polycrystalline manganites. By introducing a distribution function averaging conductivity deduced from spin-polarized tunneling model grains, we obtain general expression temperature dependence resistance can reproduce experimental data observed The present provides information microscopic mechanism.