Magnetic and transport properties of La0.3Ca0.7Mn0.9T0.1O3 (TÂ =Â Cr, Fe, and W)

We have carried out structural, magnetic and magneto transport measurements of the electron-doped manganite La0.3Ca0.7MnO3 substituted with 10% of Cr, Fe and W on the Mn site. The substitution by Cr, Fe and W suppresses the charge order transition present at 260 K in the parent compound. All the samples show a semiconducting behavior. Whereas the parent compound does not show any magneto resistance (MR) even in a field of 14 T, a maximum MR of 6% in 5 T at 25 K is observed for the Cr substituted sample that is attributed to a spin-cluster glass like states induced by Cr. The Fe and W substituted samples showed a MR of 1.5 and 3%, respectively which may be attributed to a smaller number of FM domains/spin-clusters and to an increase in anti-ferromagnetic interaction.