Magnetic and electrical studies on La0.4Sm0.1Ca0.5MnO3 charge ordered manganite

We have reported in this work the effect of the partial substitution of lanthanum by samarium on the structural, electrical and magnetic properties of La0.5Ca0.5MnO3. The magnetic study indicated that substitution promotes charge ordering and weakens ferromagnetism. Below TC=123 K, the compound La0.4Sm0.1Ca0.5MnO3 is a mixture of ferromagnetic and charge ordered antiferromagnetic domains. Between TC and TCO=215 K, the structure is paramagnetic with the presence of antiferromagnetic domains. The fractions of the coexisting magnetic phases are highly dependent on the applied magnetic field value. Resistivity measurements reveal the presence of an insulating-metal transition at Tρ=123 K. The equality between TC and Tρ indicates the presence of a correlation between magnetization and resistivity. For only 1 T applied field, we have reported a colossal value of magnetoresistance reaching 73% around TC. The origin of this high value is attributed to phase separation phenomenon.