Structure, transport and magnetism of La0.67Ca0.33Mn1−xTaxO3

For the first time, the effect of Ta5+ substitution at the Mn site of La0.67Ca0.33MnO3 compound is reported. A significant increase in lattice parameters and unit cell expansion indicate larger structural modification upon substitution. The ferromagnetic-metallic ground state is modified to a cluster glass insulator for x>0.03. The observed suppression of the ferromagnetic transition temperature Tc of ∼39 K/at% might be the highest reported in Mn-site substituted La0.67Ca0.33MnO3. The well-known effects of changed carrier density, larger average ionic radius at Mn site and dilution of Mn sublattice appear insufficient to explain this strong suppression of TC.