Tuning the spin-flip gap in transition-metal magnets by alloying

We report angle-resolved photoemission measurements of the effects of alloying on the spin-polarized electronic states of ferromagnetic transition metals. We observe that the minimum energy for spin-flip scattering of $d$ electrons (the so-called “Stoner gap” in itinerant ferromagnets) is governed by the upper limit of the majority $d$ bands. This Stoner gap can be tuned by alloying, which correspondingly alters the polarization of spin currents and lifetime of spin states in designer magnetic alloys for spintronic devices.

Figure 1

EDCs of occupied electron states at X for Ni and Ni alloys, with $h\nu =15\mathrm{eV}$. Tick marks indicate the position of the Doniach-Sunjic-shaped peaks.