53 research outputs found
Magnetic Structure in Fe/Sm-Co Exchange Spring Bilayers with Intermixed Interfaces
The depth profile of the intrinsic magnetic properties in an Fe/Sm-Co bilayer
fabricated under nearly optimal spring-magnet conditions was determined by
complementary studies of polarized neutron reflectometry and micromagnetic
simulations. We found that at the Fe/Sm-Co interface the magnetic properties
change gradually at the length scale of 8 nm. In this intermixed interfacial
region, the saturation magnetization and magnetic anisotropy are lower and the
exchange stiffness is higher than values estimated from the model based on a
mixture of Fe and Sm-Co phases. Therefore, the intermixed interface yields
superior exchange coupling between the Fe and Sm-Co layers, but at the cost of
average magnetization.Comment: 16 pages, 6 figures and 1 tabl
Driven lattice glass as a ratchet and pawl machine
Boundary-induced transport in particle systems with anomalous diffusion
exhibits rectification, negative resistance, and hysteresis phenomena depending
on the way the drive acts on the boundary. The solvable case of a 1D system
characterized by a power-law diffusion coefficient and coupled to two particles
reservoirs at different chemical potential is examined. In particular, it is
shown that a microscopic realisation of such a diffusion model is provided by a
3D driven lattice-gas with kinetic constraints, in which energy barriers are
absent and the local microscopic reversibility holds.Comment: 12 pages, 4 figures, minor change
High magnetization FeCo/Pd multilayers.
We have fabricated multilayer samples with varying superlattice periodicity and interlayer thicknesses to determine the nature of the enhanced moment in this intriguing thin film system. Magnetic characterization experiments show an enhanced magnetic moment in the multilayers as compared to a single layer film containing the same amount of FeCo. However, since the magnetization is defined as the magnetic moment divided by the sample volume, the sample exhibits an overall reduction in the magnetization when the volume of the Pd layers is also taken into account. Our experimental findings are also supported by theoretical calculations which identify the origin of the increased magnetic moment in the multilayer system. Polarized neutron reflectivity experiments will be used to determine the lateral distribution of the magnetization in a number of superlattice samples. © 2008, American Vacuum Societ
Frozen O layer revealed by neutron reflectometry
A 63 Å thick film originating from frozen air on a solid substrate has been investigated via neutron reflectometry. The experiment shows that neutron reflectometry allows performing chemical surface analysis by quantifying the composition of this frozen layer and identifies the film to be frozen oxyge
- …