Method

The purpose of this procedure is to measure the intensity and polarization of the specularly reflected electron beam from $Co/Cu(001)$, as a function of cobalt thickness, incident electron energy, and incident electron beam current. This description of the procedure has been constructed in a modular way, in the sense that a broad-brush view of the procedure is given, with references to later sections, which give finer details of each step; there are several levels of detail. This section has been constructed in this unusual fashion, because the author, aware of the general view that best practice in computer programming is to arrange the instructions, which describe what is to be done, in this fashion, is keen to investigate whether the same principle applies to natural-language descriptions of what has been done. Some of the very fine details are to be found in an appendix (appendix A.)

1. The one of the two rotational motion drivers (section 4.1,) which had a horizontal axis of rotation, perpendicular to the surface of the $(001)$ copper crystal, was used to orient the $[100]$ axis of the crystal vertically within $5^{\circ}$, using visual inspection and a previous identification, by low-energy electron diffraction, of the orientation of the crystalline axes relative to the crystal's cut faces.
2. The $(001)$ copper crystal (section 4.1,) was cleaned in an ultra-high vacuum chamber (figure 4.2,) according to the procedure in section 4.4.1, eight times. The reasons for choosing eight as the number of cycles are discussed in section 5.4. The resulting clean, well-ordered copper surface was named ``substrate 9,'' to continue the numbering sequence used in preliminary experiments (sections 5.4, 5.5.)
3. Polarized electron reflection measurements were conducted, according to the procedure in section 4.4.3.
4. Cobalt was added to the sample, and the resulting film subjected to a series of polarized electron reflection measurements, according to the procedure in section 4.4.2, seven times.