High-frequency susceptibility of a weak ferromagnet with magnetostrictive magnetoelectric coupling: Using heterostructures to tailor electromagnon frequencies

In the first part of this work we calculate the high-frequency magnetoelectric susceptibility of a simultaneously ferroelectric and canted antiferromagnetic (also known as weak ferromagnetic) thin film with magnetostrictive magnetoelectric coupling. We show that a dynamic coupling exists between the ferroelectric and optic antiferromagnetic excitations. In the second part of the paper, we calculate, using an effective medium method, the susceptibility of a heterostructure comprising alternating thin films of such a material together with a ferromagnet. Dipolar magnetic fields serve to couple the ferromagnetic and optic antiferromagnetic modes, which in turn couples the ferromagnetic and ferroelectric excitations. This provides a mechanism for creating electromagnon modes in the microwave regime which may be useful for applications.