Electric, magnetic, and thermo-electric properties of Cr doped La0.8Ca0.2Mn1−xCrxMnO3 manganites

• Pristine and Cr-doped samples show metal–insulator transition.
• TMI and TC both decrease with Cr-content.
• Magnetic data shows that MZFC and MFC bifurcate below Curie temperature.
• High temperature thermoelectric power data follows small polaron hopping model.

A detailed study of the structural, magnetic, magneto-transport and thermoelectric properties of polycrystalline La0.8Ca0.2Mn1−xCrxMnO3 (0TMI) is well described using SPH model. However, the resistivity data in the whole temperature range is analyzed using a phenomenological model based on phase segregation of ferromagnetic metallic and paramagnetic insulating regions. Thermoelectric power, S measurements were performed to understand the conduction mechanism and to ascertain the types of charge carrier responsible for conduction. It is observed that pristine as well as Cr-doped compounds show positive value of S which demonstrates that the charge carriers are holes.