Tuning magnetic properties by roll-up of Au/Co/Au films into microtubes

Au/Co/Au trilayers are fabricated by tilted deposition on prestructured polymer sacrificial layers. The metal trilayers are released by selectively dissolving the sacrificial layer and roll-up into microtubes. Magnetization properties are strongly affected by the roll-up process. In addition to a modified shape anisotropy, the magnetostrictive anisotropy due to the anisotropic stress release is reversed. Low temperature measurements support the presence of significant exchange bias in these rolled-up structures.