Excitations and spin correlations near the interface of two three-dimensional Heisenberg antiferromagnets

Magnetic excitations and spin correlations near the interface of two spin-12 Heisenberg antiferromagnets are considered using the spin-wave approximation. When the interaction between boundary spins differs essentially from exchange constants inside the antiferromagnets, quasi-two-dimensional spin waves appear in the near-boundary region. They eject bulk magnons from this region, thereby dividing the antiferromagnets into areas with different magnetic excitations. The decreased dimensionality of the near-boundary modes leads to amplified nearest-neighbor spin correlations in the interface area.

► Excitations near the interface of two Heisenberg antiferromagnets are considered.
► Different quasi-two-dimensional spin waves may appear in the interface region.
► The interface modes eject bulk modes from the near-boundary region.
► The interface modes produce amplified spin correlations near the boundary.