Effect of a Jahn-Teller ion on the ground states of Fe2+ and Ni2+ ions in spinel ferrites

Abstract
The influence of crystal distortion due to a Jahn‐Teller mechanism on lattice constant, Curie temperature, magnetization, and geff has been investigated by substituting Cu2+ ions in FeZn and NiZn ferrites. The observed results have been analyzed on the basis of exchange, spin orbit, and Jahn‐Teller mechanisms. The changes exhibited on copper substitution in the two spinels have sharp differences. These have been attributed to the difference in the ground state of the divalent ions.