Magnetic thin films having a lateral nanostructural periodicity

Magnetic and magnetoresistive properties of thin films deposited on periodically structured substrates are studied. We used a thermodynamical heat treatment to activate the step bunching phenomena on vicinal Si(111) substrates misoriented towards [112̄]. Then, Co or FeNi magnetic layers have been grown, with thicknesses ranging between 20 and 100 Å. Transmission electron microscopy experiments reveal a lateral pseudoperiodic variation of the epitaxial relationship of the metallic layers. Magnetometry measurements reveal an in-plane uniaxial magnetic anisotropy with the easy axis parallel to the step direction. We discuss the relative contributions of magnetocrystalline and shape effects to the anisotropy. Surprisingly, the angular dependance of the anisotropic magnetoresistance reveal a single-domain behavior and a magnetization reversal by rotation, with an active area as large as 700 μm×100 μm. We discuss the influence of the magnetic layer thickness on the magnetization reversal process.