Figure 1
From: Time-dependent exchange creates the time-frustrated state of matter
The origin of the retarded superexchange spin-spin interaction in a granular multiferroic. The wave functions of electrons located at adjacent magnetic metallic granules (spheres) overlap in the ferroelectric medium (yellow semitransparent environment) to form the exchange integral J depending on the frequency through the ferroelectric permittivity \(\varepsilon (\omega )\). In time representation, J(t) is the time-retarded quantity. (a) Granules are superimposed over the dielectric substrate. (b) Granules are immersed into the ferroelectric environment.
