Kim Byung Hoon, Kim Jun Sung, Park Tae Hoi, Lee Dea Su, Kim Kyung Hyun, Kim Bog G, Park Yung Woo
School of Physics and Astronomy and Nano Systems Institute, National Core Research Center, Seoul National University, Seoul 151-747, Korea.
J Phys Condens Matter. 2007 Jul 25;19(29):296205. doi: 10.1088/0953-8984/19/29/296205. Epub 2007 Jul 5.
Polycrystalline samples of Bi(0.5-y)La(y)Sr(0.5)MnO(3) (0.0≤y≤0.4) (BLSMO) have been synthesized to investigate the Bi(3+) lone-pair effect on the long-range charge-ordering (CO) state. Since the ionic size of La(3+) is similar to that of Bi(3+) and the Mn valence state does not change with La doping, we obtained the Bi lone-pair effect on the CO state without disturbance by other effects. The resistivity ρ(T) and thermoelectric power S(T) of BLSMO have been measured. A hysteretic behaviour was observed in both ρ(T) and S(T) for y = 0.1 and 0.2. From the onset of the hysteretic behaviour, we defined a charge-ordering temperature (T(CO)) and compared it to that of Bi(1-x)Sr(x)MnO(3) (BSMO). Finally, we found that the Bi(3+) lone pairs play an important role in the anomalously high T(CO) in BSMO.
