Magnetostatic surface waves in an FM/LH/FM sandwiched structure

Properties of magnetostatic surface waves in a magnetic structure with one left-handed material (LHM) film sandwiched between two ferromagnetic (FM) films are discussed, where FM films are magnetized to be saturated by an external field parallel to the film surfaces and the LHM film has a constant and negative magnetic permeability. Besides the surface magnetostatic wave lying in the same frequency range as that of a single film, two new branches of surface magnetostatic waves with negative group velocity are found in different frequency ranges. The new branches propagate along the inner surface of an FM film, but the other propagates along the outer surface.