Effect of magneto-structural phase coexistence in MnAs on the magnetic behavior of MnAs/Fe bilayers

G. ALEJANDRO , L. B. STEREN, J. MILANO, M. EDDRIEF, AND V. H. ETGENS

Estambul, Turquia

Conferencia; International Conference on Nanoscale Magnetism; 2007

INMN

We present ferromagnetic resonance (FMR) measurements performed on MnAs/Fe bilayers, from 230 K to 385 K, at a microwave frequency of 9.4 GHz. Two main lines can be identified in the FMR spectra in the coexistence region of a and b phases: one of them is unambiguousy associated to the FMR of the Fe layer. The other one, near 3000 Oe, could be associated to the paramagnetic resonance of Mn. ions. The general appearance of the FMR spectra is strongly temperature dependent in the studied range. The resonance field, linewidth, and  shape of Fe line is strongly altered in the MnAs coexistence region, where a severe drop of the resonance field is observed. In summary, the temperature dependence of the iron resonance nicely follows the a-b transition of the underlying MnAs layer, becoming a clear signature of the phase transition in the underlying MnAs layer.