Possibility of magnetoelectric effect in antiferromagnetic RFe₂O₄

Abstract

We report the magnetoelectric effect of a polycrystalline sample of a triangular Ising antiferromagnet ErFe₂O_4-δ, in which the existence of short range charge ordering was inferred from the neutron and dielectric studies. The sign of the magnetoelectric signal was reversed at 77 K, when the electric or magnetic field was applied in the opposite directions during cooling the specimen down to 77 K. The sign of the signal was independent of the direction of the static bias magnetic field in the range above 150 K. The signal was maximum at 183 K. We suggest a relation between the origin of the magnetoelectric effect and the dielectric relaxation due to an electron hopping between Fe^3- and Fe²⁺ sites.

Key Words:

• RFe₂O₄
• ErFe₂O₄
• magnetoelectric effect
• dielectric relaxation
• electron hopping
• charge order