Figure 11.

Process of virtual charge transfer and crystal structure

(A) Crystal field splitting of the 5-fold degenerate d orbitals of Cr³⁺ ions (3d³) in a cubic environment that splits the d-level into 2-fold degenerate e_g and 3-fold degenerate t_2g levels. The arrows represent the spins of chromium. We schematically show the virtual charge transfers, leading to FM and AFM states, respectively.

(B) Refined crystal structure of RECrO₃ in one unit cell (solid lines) with Pbnm space group (No. 62). The RE, Cr, O1, and O2 ions are labeled. J₁ and J₂ represent the NN spin-exchange parameters within the ab plane and along the c axis, respectively.