Gd. Waddill et al., PROBING SURFACE AND THIN-FILM MAGNETIC-STRUCTURE WITH CIRCULARLY-POLARIZED SYNCHROTRON-RADIATION, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 14(4), 1996, pp. 3152-3159
A new group of techniques predicated on the availability of a tunable
source of circularly polarized soft x-rays show tremendous potential f
or advancing the understanding of magnetic nanostructures. These techn
iques involve use of circularly polarized radiation as probes in x-ray
absorption and x-ray photoemission and photoelectron diffraction stud
ies, and provide unique information about the element specific magneti
c moments and magnetic structure of thin films, interfaces, and surfac
es. Examples of each technique will be discussed with emphasis given t
o the recently demonstrated first observation of spin-dependent photoe
lectron diffraction using circularly polarized x-rays. This technique
promises the direct, element specific determination of local magnetic
structure on an atomic scale, and will be of tremendous utility in the
effort to establish structure-property relationships in magnetic nano
structures. Circularly polarized x-rays are used to produce spin-polar
ized photoelectrons from the Fe 2p spin-orbit doublet. Intensity asymm
etries of up to similar to 3% are observed for the 2P(3/2) sublevel. T
hese asymmetries depend on the relative orientation of the x-ray polar
ization vector and the sample magnetization as well as upon the photoe
lectron kinetic energy and emission direction. Multiple scattering cal
culations are found to reproduce both the observed energy and angular
asymmetry variations. Strategies to increase the measured effect are a
lso discussed. (C) 1996 American Vacuum Society.