In situ lattice dynamics of GaAs/Fe core/shell nanowires

Nanowires (NWs) that combine a semiconductor and a ferromagnet in a core-shell geometry gained attention as building blocks of spintronic and magnetic data storage devices, and constitute an excellent testbed for fundamental research on quantum phenomena in quasi-1D heterostructures. Recently, unexpectedly strong confinement of acoustic phonons was observed in GaAs NWs with diameters significantly exceeding the phonon mean free path in this material, implying that strong phonon confinement should also be present in their ferromagnetic shell. The aim of this proposal is to continue the systematic study (initiated in the exp. MA-5570) of the lattice dynamics of the Fe shell in the GaAs/Fe core/shell NWs as a function of GaAs-core diameter and Fe-shell thickness by measuring the Fe-partial phonon density of states by in situ nuclear inelastic scattering.