Ferrimagnetic Clusters as the Origin of Anomalous Curie-Weiss Behavior in ZnFeO Antiferromagnetic Susceptibility.

Different studies carried out in the last three decades on the magnetic susceptibility of the spinel ZnFeO ferrite have revealed the positive character of its Curie-Weiss temperature, contradicting its observed antiferromagnetic behavior which is characterized by a well-defined susceptibility peak centered around the Neel temperature (10 K). Some approaches based on ab initio calculations and mixture of interactions have been attempted to explain this anomaly. This work shows how for very low values of the inversion parameter, the small percentage of Fe atoms located in tetrahedral sites gives rise to the appearance of ferrimagnetic clusters around them.

Unveiling the Hidden Entropy in ZnFeO.

The antiferromagnetic (AFM) transition of the normal ZnFeO has been intensively investigated with results showing a lack of long-range order, spin frustrations, and a "hidden" entropy in the calorimetric properties for inversion degrees δ ≈ 0 or δ = 0. As δ drastically impacts the magnetic properties, it is logical to question how a δ value slightly different from zero can affect the magnetic properties. In this work, (ZnFe)[ZnFe]O with δ = 0.