Modulated Crystal Structure of Charge-Orbital Ordered Manganites

摘要

The crystallographic superstructures were investigated for charge-orbital ordered manganites, Nd_(1-x)Sr_(1+x)MnO_4 (x = 2/3, 3/4), by low-temperature high-resolution electron microscopy. Transverse and sinusoidal structural modulations were successfully observed in the images at 80 K. The observation implies that a new kind of 'Wigner-crystal' model accompanied with a charge-density wave of e_g electrons best explains the charge-orbital ordered state.