Discovery of room temperature multiferroicity and magneto-electric coupling in Fe3Se4 nanorods

We report for the first time, that Fe3Se4 is a room temperature, type-II multiferroic with magnetoelectric coupling. We observed the coexistence of coupled ferrimagnetic and ferroelectric ordering in Fe3Se4nanorods well above room temperature, which is a hard magnet with large magnetocrystalline anisotropy. For the first time, we observed spontaneous, reversible ferroelectric polarization in Fe3Se4 nanorods below the magnetic Curie temperature. The coupling is manifested by an anomaly in the dielectric constant and Raman shift at Tc. We do not completely understand the origin of the ferroelectric ordering at this point however the simultaneous presence of magnetic and ferroelectric ordering at room temperature in Fe3Se4 along with hard magnetic properties will open new research areas for devices.