MnGe magnetic nanocolumns and nanowells.

We report a 'superlattice' growth method to produce well-aligned magnetic MnGe nanocolumns and nanowells by using low-temperature molecular-beam epitaxy. Both structural and magnetic properties show strong evidence of Mn(5)Ge(3) precipitates and lattice-coherent nanostructures with different blocking temperatures. Magnetotransport measurements reveal positive and negative magnetoresistances for the nanowells and nanocolumns, respectively. This distinction can be explained by different spin scattering mechanisms under magnetic fields. Our results suggest a new growth strategy to achieve reproducible MnGe nanostructures, which facilitates the development of Ge-based spintronics and magnetoelectronics devices.