Direct Release of Synthetic Antiferromagnetic Nanoparticles Fabricated by Defect-Free Thermal Imprinting

We report an improved process, using a defect-free thermal imprinting process that directly releases homogeneously patterned lithographic nanoparticles from a large-area wafer to water. Our method has a substantially larger yield and avoids all the pitfalls that are associated with the sacrificial layers in the traditional imprinting methods. By using an ethylene tetrafluoroethylene mold and a bi-layer resist lift-off, defect-free imprints were achieved in areas larger than 1 × 1 cm 2 . Illustrating the effectiveness of this method, high-quality planar Fe/Ta multi-layered magnetic nanoparticles, 300 nm in diameter, were deposited by ion-beam sputtering and their basic magnetic properties are characterized. These particles prepared by direct release with tunable magnetic properties and good engineering possibilities are ideal for a wide range of applications, including those specifically for biomedicine.