Antiferromagnetic perovskites

Figure 17 Magnetic structures for antiferromagnetic perovskites. The open and solid black spheres represent sublattices of opposing spin...

Table 7.1 Antiferromagnetic perovskites and perovskite-related phases...

Susceptibility measurements of cubic fluoroperovskites AMeFj and the corresponding compounds AaMeF4 showed the antiferromagnetism in the latter being reduced to about 2/3 that of the perovskit compound containing the same cation Me. This is quite in accordance with the reduction of superexchange from 3 to 2 dimensions 268, 271). 

The structure of KCrF3 is derived from the perovskite structure by a tetragonal distortion4. An antiferrodistortive coupling occurs between half-filled dz orbitals and empty d 2 yj orbitals. The superexchange interaction d°z y2 - p - dz2 leads to ferromagnetic layers, antiferromagnetically bound via the empty dx2 y2 orbitals. 

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