Rare earth metals exhibit a rich spectrum of bulk magnetic order. When they are multilayered, these metals offer the possibility of producing a wide variety of tunable magnetic properties. The authors present an analysis of the magnetic excitations appropriate to the ferromagnetic, spiral and antiferromagnetic phases of such multilayers. They find that the interfaces play a very important role in determining the ground state of the system, and systems with identical spin equilibrium configurations can also have significantly different spin excitations, suggesting corresponding differences in their thermodynamic properties.