Spin polarized x-ray photoelectron spectroscopy
A new electron spectrometer for spin polarized x-ray photoelectron spectroscopy (XPS) study is described. With a plane mirror analyzer (PMA) connected in between the hemispherical electron energy analyzer and the low energy diffuse scattering electron spin polarimeter, it is possible to simultaneously measure both transverse and longitudinal electron spin polarization components. The operating characteristics of the spectrometer are demonstrated on X1B, an undulator based soft x-ray beamline at the National Synchrotron Light Source (NSLS). Results obtained from simple ferromagnetic systems such as Fe and Co are consistent with existing data. Cr and Mn thin films on Fe(100) are studied experimentally. The spin polarized core level photoemission from a Cr monolayer on Fe(100) shows that the Cr monolayer is ferromagnetically aligned within the plane but antiferromagnetically aligned with respect to the Fe substrate. With the deposition of a second monolayer of Cr, it is no longer possible to measure a net spin polarization in the Cr 3{ital p} level. This is consistent with a picture in which the Cr layers couple antiferromagnetically with respect to each other. Spin polarized Mn 3p spectra of Mn overlayer on Fe(100) with different Mn film thicknesses at both room temperature and {minus}120{degrees}C show no measurable net polarization. The results indicate that the Mn overlayer on Fe(100) cannot form a ferromagnetic structure above temperature {minus}120{degrees}C. The complexities of the spin polarized core level spectra are examined by simple modeling. This model is based on the core hole atomic multiplet structure and quenching of the d electron orbital component in 3d transition metals. Based on this simple model, the experiment results from a monolayer of Cr on Fe(100) are shown to be consistent with a predicted local magnetic moment of {approximately}3 Bohr magnetons on the Cr site.
- Research Organization:
- City Univ. of New York, NY (United States)
- OSTI ID:
- 39311
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); PBD: 1993
- Country of Publication:
- United States
- Language:
- English
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