X-ray resonant scattering study of spin-density waves in a superlattice
The discovery of interlayer coupling in multilayers through nonmagnetic spacer layers was soon followed by the discovery of GMR, and this paved the way for the revolution in magetoelectronics. It is generally accepted that long-range order is established by the magnetic material inducing a spin-density wave in the conduction band of the nonmagnetic element, but neutron scattering is not sensitive to the polarization of the conduction band. Direct evidence for the existence of induced ordering may be obtained using x-ray magnetic circular dichroism. This technique measures the spin and orbital moments averaged over the multilayer structure, but cannot directly determine the spatial modulation of the magnetization. A diffraction method, such as x-ray resonant scattering shares the species sensitivity of XMCD, and has the added advantage that spatial information is retained. We have observed the conduction-electron spin-density waves responsible for magnetic coupling in multilayers for the first time using resonant x-ray scattering from Nd/Pr multilayers.
Goff JP, Sarthour RS, McMorrow DF, Yakhou F, Stunault A, Vigliante A, Ward RCC, Wells MR
J. Phys.: Condens. Matter 11, L139 (1999).