Charge and orbitally ordered

Fig. 52. Charge and orbital ordering in the orthorhombic basal plane for (a) x = 0, (b) x = 0.5 for localized e orbitals, and (c) Mori et al. (1998a, 1998b) model for x = 2/3.

Figure 18. Charge and orbital Ordering in Lai-j,Ca MnOi (a) x — 0.50, (b) x = 0.67. Open circles represent Mn4+ and lobes show e, orbitals of Mn3+. Charge modulation wavelengths are 11 and 16.5 A for x = 0.50 and 0.67, respectively (following Cheong).

In this article, we discuss spin, charge and orbital orders in transition metal oxides, in particular, in the rare-earth manganites which have become famous since 1993 owing to the phenomenon of colossal magnetoresistance (CMR) exhibited by them (Rao Raveau 1998). We also touch upon the issue of electronic inhomogeneities we discuss the signatures of the presence of such inhomogeneities and theoretical approaches to understand the same. 

Figure 8.13 Charge and orbital ordering in manganites (a) thed, orbital (b) theorbital ordering in LaMnO (axes refer to the Pbnm setting) (c) charge and orbital ordering in Lag Cag MnO (axes refer to Pnma setting). In (b) and (c) only the Mn cations are shown...

P. Mahadevan, K. Terakura, and D. D. Sarma, Spin, charge, and orbital ordering in Lao sSri 5Mn04, Phys. Rev. Lett. 87 (2001), 066404-066407. 

Murakami, Y, Kawada, H., Kawata, H., Tanaka, M., Arima, T., Moritomo, H., and Tokura, Y. Direct observation of charge and orbital ordering in Lao Srj sMn04. Phys. Rev. Lett 1998, 80, 1932-1935. 

---