X-ray resonant magnetic scattering from structurally and magnetically rough interfaces in multilayered systems I. Specular reflectivity

Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois, United States
Physical review. B, Condensed matter (Impact Factor: 3.66). 05/2003; 68(22). DOI: 10.1103/PhysRevB.68.224409
Source: arXiv

ABSTRACT The theoretical formulation of x-ray resonant magnetic scattering from rough surfaces and interfaces is given for specular reflectivity. A general expression is derived for both structurally and magnetically rough interfaces in the distorted-wave Born approximation (DWBA) as the framework of the theory. For this purpose, we have defined a ``structural'' and a ``magnetic'' interface to represent the actual interfaces. A generalization of the well-known Nevot-Croce formula for specular reflectivity is obtained for the case of a single rough magnetic interface using the self-consistent method. Finally, the results are generalized to the case of multiple interfaces, as in the case of thin films or multilayers. Theoretical calculations for each of the cases are illustrated with numerical examples and compared with experimental results of magnetic reflectivity from a Gd/Fe multilayer. Comment: 44 pages, 10 figures

Download full-text


Available from: Jonathan C Lang, Apr 29, 2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: We discuss studies of the magnetic specular reflectivity of neutrons and X-rays from the exchange bias system consisting of a single crystal film of antiferromagnetic FeF2 capped with a ferromagnetic Co film cooled in an applied magnetic field below the TN of the FeF2. This system exhibits a shift of the magnetic hysteresis loop along the direction of the cooling field Hc (positive exchange bias) or in the opposite direction (negative exchange bias) depending on the magnitude of the cooling field. The use of neutrons with polarization analysis enables the spatial distribution of different vector components of the magnetization to be determined, and the use of resonant magnetic X-ray scattering enables magnetization in a compound system to be determined element-selectively. Our results show that the coupling across the interface between the relatively few uncompensated Fe spins and the more numerous Co spins is antiferromagnetic. In a large cooling field which overrides this coupling, the Fe spins are oriented along Hc and some get pinned in this direction, in turn pinning the Co spins above the interface oppositely and thus creating positive exchange bias. For sall values of Hc the Fe spins get locked in the opposite direction producing negative exchange bias. In addition a significant fraction of the Fe spins at the interface are unpinned and always align opposite to the Co magnetization.
    Superlattices and Microstructures 02/2007; 41(2):109-115. DOI:10.1016/j.spmi.2007.02.004 · 1.98 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Some recent developments in grazing incidence small angle scattering (GISAS) technique are reviewed. The emphasis is on the application of GISAS to elucidating the effects of geometrical surface constraint on self-assembled systems and the effect of modification of interfaces or molecular subassemblies to direct the formation of more complex structures.
    Current Opinion in Colloid & Interface Science 06/2005; 9(6-9):390-395. DOI:10.1016/j.cocis.2004.10.005 · 6.40 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The coupled interfacial Mn and Ru spin configurations in a SrRuO3(SRO)/SrMnO3(SMO) superlattice are investigated with x-ray resonant techniques. With an out-of-plane applied field H, a net Mn moment is induced opposite to (along) H below (above) SRO Curie temperature TC, due to changes in interfacial antiferromagnetic Ru-Mn coupling. In comparison with the Mn moment induced along an out-of-plane field below TC, the Mn moment induced along an in-plane field is five (three) times smaller below (above) TC, due to frustration in the Ru-Mn coupling. Despite its in-plane anisotropy, the G-type antiferromagnetic SMO favors out-of-plane over in-plane canting of Mn moments.
    Applied Physics Letters 11/2008; 93(19). DOI:10.1063/1.3013333 · 3.52 Impact Factor