Elastic and magnetoelastic behaviour of nanoscale magnetic multilayers

Experimental and theoretical research on elastic and magneto-elastic behavior of nanoscale magnetic multilayers is reviewed. The discovery of the “supermodulus effect” and the softening of the elastic constants as well as the experimental evidence for the existence of the intrinsic “surface magnetostriction” are discussed in detail. It has been shown that the commonly observed lattice expansion perpendicular to the film plane is not a bulk effect, but is localized at the interface between the contacting metals. A similar situation is observed in the ease of magnetoelastic strains. It is shown that the most effective technique used to study magnetostriction is the Strain Modulated Ferromagnetic Resonance (SMFMR). In addition to obtaining information on the magnetostriction constants, the SMFMR method offers the opportunity to study the interface effects, particularly it can be used to separate the intrinsic surface magnetostriction from the interface induced effects. The origin of the surface magnetostriction will be discussed and qualitatively attributed to many different mechanisms. Quantitatively the surface magnetostriction will be analyzed in terms of magnetic dipole-dipole interactions