In iron-deficient spinel ferrites containing manganese, but no other constituent of variable valency, all the manganese will not be divalent. Mn³⁺ ions tend to form strong directed semicovalent bonds in octahedral (B) sites but not in tetrahedral (A) sites. The reverse is true for Fe³⁺ ions. The antiparallel A[sbnd]B indirect exchange interaction should thus be weaker when one interacting ion is Mn³⁺ than when both are Fe³⁺. Any Mn³⁺ ions are likely to be coupled with parallel spins by double exchange with Mn²⁺ or Mn⁴⁺ ions in the same type of lattice site, The magnetic ions in either sublattice can then be considered as divided into two groups, one based on Mn³⁺ ions, and the other on Fe³⁺ ions, with different degrees of departure from antiparallelism of their net, spins to the net magnetization of the other sublattice. The molecular field approximation as applied by other authors to single ions is extended to such groups of ions, with certain provisos as to the correct interpretation to be given to the mathematical symbols used for interaction coefficients and angles between spin directions.

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directed semicovalent bonds antiparallel asbndb indirect exchange interaction b mnsup3sup spin directions interaction coefficients molecular field approximation

W. P. Osmond,.CXVI. Angles between partial magnetizations in spinel ferrites containing manganese ions of more than one valency. 1 (12),1147-1156.

W. P. Osmond,"CXVI. Angles between partial magnetizations in spinel ferrites containing manganese ions of more than one valency" 1

W. P. Osmond,"CXVI. Angles between partial magnetizations in spinel ferrites containing manganese ions of more than one valency"