Adiabatic small polaron hopping conduction in La0.7Nd0.3Mn0.8Cr0.2O3

The dc conductivity and magnetization of insulating La0.7Nd0.3Mn0.8Cr0.2O3 were measured in temperature ranges of 77-300 and 4.2-300 K, respectively. La0.7Nd0.3Mn0.8Cr0.2O3 shows a ferromagnetic transition around 130 K but the sample is insulating throughout the temperature range studied. The temperature dependence of conductivity shows that electronic transport in La0.7Nd0.3Mn0.8Cr0.2O3 is well described by the Emin-Holstein adiabatic small polaron hopping model. The polaron density extracted from conductivity measurements is about 3.0x1020 cm-3. This result agrees well with the nominal polaron density for La0.7Nd0.3Mn0.8Cr0.2O3, which is also roughly 3.0x1020 cm-3. We also derived important quantities for transport in La0.7Nd0.3Mn0.8Cr0.2O3.