Effect of high energy electron beam irradiation on the structural properties, electrical resistivity and thermopower of La0.5Sr0.5MnO3 manganites

Bulk samples of La0.5Sr0.5MnO3 manganite have been subjected to electron beam irradiation of different dosages. As a consequence, the structural and electronic transport properties viz resistivity and thermoelectric power are affected to some extent. The stoichiometric content of the sample is confirmed through Energy Dispersive X-ray spectroscopy. X-ray diffraction study of the samples (unexposed and exposed to electron beam radiation) show that the samples crystallize in a single phase rhombohedral structure. Insulating behavior is displayed in the temperature range 10-300 K investigation for all the samples. Temperature dependent thermoelectric power data reveals n-type conductivity in the entire temperature zone. At high temperatures, it is concluded through detailed analysis that both resistivity and thermopower conform to small polaron hopping model. On the other hand, variable range polaron hopping model elucidates the transport characteristics at low temperatures.