Abstract
Dy-0.5(Sr1-xCax)(0.5)MnO3 (x = 0 and x = 0.3) manganites were synthesized using sol-gel method. Both samples exhibited an insulating behavior in the whole temperature range. Even the application of 5 T magnetic fields does not change this state. Conduction mechanisms were also investigated. The I-V characteristics of both samples present Ohmic behavior at minor voltages. Magnetoresistance and electroresistance were also studied. The thermal variation of Hail resistivity of Dy0.5Sr0.5MnO3 was determined in cooling down and warming up processes revealing electron-like type of charge carriers. Temperature coefficient of resistance shows significant values for both systems making them good candidates for bolometer applications.