Effect of Li doping on the charge ordering state of La[sub 0.5]Ca[sub 0.5]MnO[sub 3].

The effect of Li doping on the charge ordering (CO) state in perovskite-type manganates La[sub 0.5]Ca[sub 0.5-x]Li[sub x]MnO[sub 3] with x=0, 0.05, 0.1, 0.15, 0.2 is investigated by transport and magnetic property measurements. The resistivity of the samples decreases with the increase of the Li-doped level. As x>=0.1, the insulator-metal (IM) transition has been induced. Accompanying the variation of transport properties, the sample undergoes the variation from antiferromagnetic order for x<0.05 to ferromagnetic (FM) order for x>=0.1. The experimental results indicate that the Li doping can destroy the CO state and induce the FM metallic (FMM) phase. These phenomena can be interpreted in terms of the strong competition between the CO state and FM phase induced by the Li[sup +] ions substitution for the Ca[sup 2+] ions. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]