Ferroelectricity in the Ferrimagnetic Phase of Fe_1-xMn_xV₂O₄

Ferroelectric and magnetic properties of Fe_1?xMn_xV₂O₄ (0≤x≤0.5) spinels are investigated on the basis of dielectric, polarization, and susceptibility measurements. Ferroelectric polarization is discovered in collinear ferrimagnetic and Yafet–Kittel magnetic phases for 0.1≤x≤0.4, which can be tuned by a magnetic field. As orbital-active Fe²⁺ is substituted with Mn²⁺, ferroelectric polarization decreases for 0≤x≤0.4 and disappears for x=0.5. We propose that the two polar components in ferroelectric polarization originate from the exchange striction mechanism and the spin-current model, respectively.