Templated Electrochemical Synthesis of Fe–Pt Nanopatterns for High-Density Memory Applications

We demonstrate an electrochemical deposition process suitable to form arrays of L10 Fe–Pt nanodots with hard magnetic properties via electron-beam lithography, template deposition, and thermal annealing. Synthesis parameters are selected by growing single and multilayer blanket films and investigating the effect of thermal annealing on the various films. We find that the fastest ordering transformation is achieved in eight-layer Fe–Pt multilayers with a sublayer thickness of 2.5 nm, while a single Fe–Pt layer or four- and twenty-layer multilayers exhibit a more sluggish ordering process due to the imperfect layering (twenty-layer) or to the limited mean free path upon annealing (single- and four-layer); the coercivity of the eight-layer Fe–Pt multilayer after annealing at 450 °C reached 6.6 kOe, whereas the single Fe–Pt layer showed only 1.0 kOe. TEM imaging and diffraction show that the L10 Fe–Pt nanodot arrays are single crystal with a (111) orientation, suggesting a facile L10 ordering when using a multilayer structure.