Magnetotransport and magnetic properties of weak ferromagnetic semiconductors: Ca doped LaCrO3

We report the magnetic and magnetotransport properties of Ca doped La1-xCaxCrO3 (x=0, 0.1, 0.2, and 0.3). Both the magnetic and transport properties are very sensitive to Ca substitution. The Neel temperature T-N decreases substantially with increasing calcium doping concentration from 290 to 160 K. A weak ferromagnetic state with large coercive fields of up to 3 T is present for the Ca doped LaCrO3. The temperature dependence of the resistivity shows that all the Ca doped com#163s are semiconducting and their resistivities decrease with increasing Ca for low doping levels. The resistivity curves show thermally activated behavior and a variable range hopping behavior at high temperatures. The magnetotransport measurements show a negative magnetoresistance. Furthermore, an anomalous peak was observed in the field dependence of magnetoresistance for the LCCO materials.