Magnetic exchange interactions in perovskite solid solutions. Part 4. The Fe3+–O–Cr3+ superexchange interaction

Abstract

A major investigation of magnetic exchange and supertransferred hyperfine field effects in perovskite solid solutions has been carried out using ⁵⁷Fe, ¹¹⁹Sn, and ¹⁵¹Eu Mössbauer resonances. The primary result has been to establish that the Fe³⁺–O–Cr³⁺ superexchange coupling in orthoferrite and orthochromite solid solutions is antiferromagnetic, and earlier contradictions have been resolved. Ferromagnetic coupling can only occur in oxides where the bond angle is close to 180°. Exchange interactions involving Mn³⁺ and Ni³⁺ have also been observed in the ¹¹⁹Sn and ¹⁵¹Eu resonances.