Effect of aluminum doping on the magneto-transport properties of La0.75Ca0.25MnO3

The influence of aluminum doping at Mn-site in La0.75Ca0.25MnO3 has been investigated, in the light of magnetotransport, and structural properties. As the aluminum concentration increases, the metal–insulator transition temperature (TP) decreases while activation energy in the insulating region (T>TP), resistivity and maximum value of magnetoresistance (MR) increases. The unit cell volume decreases slightly as the aluminum concentration increases. The observed results are analyzed in term of defect clustering due to aluminum doping at Mn-site induced random spin disorder and local strain and its effect on the magnetotransport properties.