The evolution of spin- and orbital-ordered states has been systematically investigated for a series of insulating perovskites RMnO3 (R=La,Pr,Nd,...). RMnO3 with a large GdFeO3-type distortion is regarded as a frustrated spin system having ferromagnetic nearest-neighbor and antiferromagnetic (AF) next-nearest-neighbor (NNN) interactions within a MnO2 plane. The staggered orbital order associated with the GdFeO3-type distortion induces the anisotropic NNN interaction, and yields the unique sinusoidal and E-type ("up-up-down-down") AF ordered states in the distorted perovskites with eg1 configuration.
@article{arxiv.cond-mat/0211568,
title = {Distorted Perovskite with e_g^1 Configuration as a Frustrated Spin System},
author = {T. Kimura and S. Ishihara and H. Shintani and T. Arima and K. T. Takahashi and K. Ishizaka and Y. Tokura},
journal= {arXiv preprint arXiv:cond-mat/0211568},
year = {2009}
}