It has been revealed that a Y-type hexaferrite ${\mathrm{BaSrCo}}_2{\mathrm{Fe}}_{11.1}{\mathrm{Al}}_{0.9}{\mathrm{O}}_{22}$ hosts not only an in-plane $\left(P_{ab}\right)$ but also an out-of-plane $\left(P_c\right)$ component of magnetically induced electric polarization in the double-fan magnetic phase. With an increasing in-plane magnetic field, the magnitude of $P_c$ reaches a maximum at around $2\text{T}$ and decreases as approaching the critical field $\left(3.8\text{T}\right)$ of the transition to the collinear ferrimagnetic phase. $P_c$ has also been verified to show a ${120}^{\circ }$-period oscillation as a function of the in-plane magnetic field direction. These results are reproduced by a model combining the inverse Dzyaloshinskii-Moriya interaction and the spin-dependent $pd$ hybridization mechanisms.

• Received 24 July 2019
• Accepted 30 January 2020

DOI:https://doi.org/10.1103/PhysRevB.101.100403