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Abstract The ferromagnetic resonance of a disordered A2 Fe60Al40 ferromagnetic stripe, of dimensions 5 µm × 1 µm × 32 nm, has been observed in two vastly differing surroundings: in the first case, the ferromagnetic region was surrounded by ordered B2 Fe60Al40, and in the second case it was free standing, adhering only to the oxide substrate. The embedded ferromagnet possesses a periodic magnetic domain structure, which transforms to a single domain structure in the freestanding case. The two cases differ in their dynamic response, for instance, the resonance field for the uniform (k = 0) mode at ~ 14 GHz excitation displays a shift from 209 to 194 mT, respectively for the embedded and freestanding cases, with the external magnetic field applied along the long axis. The resonant behavior of a microscopic ferromagnet can thus be finely tailored via control of its near-interfacial surrounding.

The variation of transport behavior in a mesoscopic $\mathrm{Fe}_{60}\mathrm{Al}_{40}$ wire, initially possessing the ordered $B2$ -phase structure, has been observed while inducing a phase transition to the disordered $A2$ phase. Gradual disordering was achieved using a highly focused beam of $\mathrm{Ne}^+$ -ions. Both electrical resistance and anomalous Hall effect were measured simultaneously and in situ during the local ion irradiation. The normal as well as the Hall resistivity show a peak as a function of disorder. The relationship between Hall resistivity and normal resistivity shows the presence of two distinct transport regimes during the phase transition. Ex situ field- and temperature-dependence measurements show that it is necessary to consider the effect of scattering from magnetic clusters to understand these different regimes in transport properties.