Soft X-Ray Appearance Potential Spectra of the Rare Earths

Abstract

We have measured the M5, M4 Soft X-Ray Appearance Potential Spectra (SXAPS) of the lanthanide series rare earths. Lutetium and ytterbium do not show the huge signal response characteristic of the other rare earths. This is to be expected since both metals have a closed 4f shell containing 14 electrons. More striking is the lack of significant SXAPS response for ytterbium oxide (Yb2O3) in which a single 4f Yb vacancy is known to exist. The contribution to this spectrum from the local density of states is more than an order of magnitude smaller than the intense peaks seen in the other rare earths. The M5 and M4 spectra of the other rare earths are split into a series of lines. All of the intense SXAPS lineshapes are explained in terms of a resonance in the bremsstrahlung emission. The excitations involve a resonant scattering interaction in which both the incident electron and a d core electron scatter into the atomic 4f level.

Magnetic Properties of Amorphous FexSi1−xFilms. I. Transverse Susceptibility, Structure Constant, and Local Anisotropy

“…A ripple contribution to the transverse susceptibility has been found in amorphous Fe,Sil-, films. Consequently, a "random anisotropy model" with an appropriate correlation length to set up the case of "thin film-fine scale inhomogeneity" in the micromagnetic models of Harte [4] and Hoffmann [5], may explain our experimental results.…”

“…It has been suggested [3] that a similar model may also be applicable in the case of transition metal-metalloid amorphous alloys. As will be discussed later (Section 3), if a random anisotropy model is applied to amorphous films of soft ferromagnetic materials, the micromagnetic models developed by Harte [4] and Hoffmann [5] for polycrystalline films are useful to explain some of their magnetic properties, such as magnetization ripple [6].…”

Resonant Behaviour of X‐Ray Intensities in Metallic Nickel Near the 2p Threshold

“…Fig. 4 shows a comparison of the experimental XCEF spectrum and a calculated curve using (3). According to the interpretation of the XCEF, El and E, are very close to the binding energy of 851.8 and 868.8 eV, respectively, and they are therefore no free parameters.…”