Magnetism in La0.7Pb0.3(Mn0.9TM0.1)O3 (TM=Fe, Co, Ni) CMR perovskites

Abstract In this work, we present structural and magnetic properties of La 0.7 Pb 0.3 (Mn 0.9 TM 0.1 )O 3 (TM=Fe, Co, Ni) manganites. Samples were fabricated by the sol-gel low temperature method. At room temperature, the first structural characterization of these phases gave the rhombohedral space group (R-3c). All the compositions show ferromagnetic behaviour and magnetoresistance. The measured magnetic moment (at low temperature) and the Curie temperature continuously decrease, with respect to the undoped composition, as Mn ions are substituted by Ni, Co, or Fe, respectively. The measured magnetoresistance reaches 65% for the Fe-doped composition. From these results, the influence of the TM doping is interpreted in terms of ferro- or antiferromagnetic competing Mn 3+ -Mn 4+ and TM 3+ -Mn 4+ interactions.