Effect of Ga-doping on magnetic and electrical properties of La2/3Sr1/3Mn1−xGaxO3 (0<x⩽0.5)

We studied the effect of substitution of Mn by Ga in the La1−xSrxMn1−xGaxO3 system. We find that the Curie temperature strongly decreases as the content of Ga increases. The x<0.3 samples order ferromagnetically while the x>0.3 samples show a spin-glass like behavior. Electrical properties also vary significantly with x. For x>0.3, the system is semiconducting while for x⩽0.2 it exhibits a metal–insulator transition. The metallic behavior onset occurs close to the Curie temperature for x<0.05 whereas the resistivity maximum appears well below the magnetic ordering temperature for 0.05⩽x⩽0.2.