Figure 1

(a) Diagram of experimental setup showing the structure of the samples, the direction of the incident x-rays, and the position of the measuring photodiodes (I₀ and I). (b) Examples of XMCD spectra taken at ~6 K for Ni (i) and Gd (ii). The XMCD was measured at the Ni L₃ and Gd M₅ absorption edges, respectively, marked by dotted lines. The two signals μ⁺ and μ⁻ are from positive and negative saturation, while Δμ is the difference between the two, vertically offset for clarity. (c) Hysteresis loops measured between 5 and 10 K (low T), and 45 and 65 K (high T), that are representative of the three observed behaviours (N.B. Axis on all plots identical). The (total) Ni and Gd thicknesses of each of the samples are (from left to right): 5 nm Ni and 4.5 nm Gd, 6 nm Ni and 8 nm Gd, and 8 nm Ni and 6 nm Gd. The last sample is the same as that from which the XMCD spectra are shown in (b).