Bismuth iron garnet Bi3Fe5O12: A room temperature magnetoelectric material

The possibility to control the magnetic properties of a material with an electric field at room temperature via magnetoelectric (ME) coupling is highly desirable for modern applications. Here, we report the unambiguous observation of ME coupling above 300K that is linear with respect to the electric field in a bismuth iron garnet (BIG). The ferromagnetic resonance technique with electric field modulation was used to quantify ME coupling in Bi3Fe5O12 thin films and patterned structures grown on garnet substrates. The measured coupling value is comparable with that observed for prototypal magnetoelectric Cr2O3. On the basis of our experimental results, the strength of this linear ME coupling is directly linked to the presence of bismuth ions inducing strong spin orbit coupling and to the appearance of local magnetic inhomogeneities related to the magnetic domain structure. The unprecedented combination of magnetic, optical, and magnetoelectrical properties in the BIG is expected to trigger significant interest for technological applications as well as for theoretical studies. Published by AIP Publishing.