We present size dependent spin and orbital magnetic moments of cobalt (Con+, 8 ≤ n ≤ 22), iron (Fen+, 7 ≤ n ≤ 17), and nickel cluster (Nin+, 7 ≤ n ≤ 17) cations as obtained by X-ray magnetic circular dichroism (XMCD) spectroscopy of isolated clusters in the gas phase. The spin and orbital magnetic moments range between the corresponding atomic and bulk values in all three cases. We compare our findings to previous XMCD data, Stern-Gerlach data, and computational results. We discuss the application of scaling laws to the size dependent evolution of the spin and orbital magnetic moments per atom in the clusters. We find a spin scaling law “per cluster diameter,” ∼n−1/3, that interpolates between known atomic and bulk values. In remarkable contrast, the orbital moments do likewise only if the atomic asymptote is exempt. A concept of “primary” and “secondary” (induced) orbital moments is invoked for interpretation.

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See supplementary material at http://dx.doi.org/10.1063/1.4929482 for a comparison of experimental and theoretical spin magnetic moments in μB/atom (Table S3a). In Table S3b, we show a comparison of experimental orbital magnetic moments in μB/atom. In Figure S1, we show spin and orbital magnetic moments of size selected clusters in comparison to conceivable trends that would interpolate between bulk metals and cationic atoms. In Figure S2, we show a comparison of spin and orbital magnetic moments for Fen+, Con+, and Nin+ clusters from this study and data obtained by Lau et al. In Figure S3, we show theoretical data on the spin magnetic moments of Fe clusters. In Figure S4, we show theoretical data on the spin magnetic moments of Co clusters. In Figure S5, we show theoretical data on the spin magnetic moments of Ni clusters.

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