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

Abstract For the first time, the effect of Ta 5+ substitution at the Mn site of La 0.67 Ca 0.33 MnO 3 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 T c of ∼39 K/at% might be the highest reported in Mn-site substituted La 0.67 Ca 0.33 MnO 3 . 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 T C .