Magnetoelectric properties of room-temperature spirally ordered ${\mathrm{Sr}}_3{\mathrm{Co}}_2{\mathrm{Fe}}_{24}{\mathrm{O}}_{41}$ hexaferrite slabs have been measured. A physical model in this paper referred to as the “slinky helix” model is presented to explain the experimental data. The measured properties include the magnetic permeability and the strain, all as a function of the electric field $\mathbf{E}$. Upon application of an electric field to slabs of Sr Z-type hexaferrite, it exhibits broken symmetries for time reversal and parity. This is the central feature of these magnetoelectric materials.

• Received 28 November 2011

DOI:https://doi.org/10.1103/PhysRevB.86.024430