Superexchange interaction in the A-site ordered perovskite YMn sub(3) Al sub(4) O sub(12)

Crystal structure and magnetic ordering in YMn sub(3) Al sub(4) O sub(12) are determined by neutron powder diffraction measurement, indicating that S = 2 spins of the A'-site Mn super(3+) ions are ordered in G-type antiferromagnetic (AFM) arrangement in the Im3 cubic crystal structure. Using the first-principles electronic structure calculations, it is found that the AFM spin structure is stabilized by the nearest-neighbour (NN) exchange interaction. The underlying mechanism of the NN exchange is revealed to be the antiferromagnetic Mn-O-Mn superexchange interaction from the calculations of electronic transfer integrals.