Exchange Bias in FePt-FePt3 Thin Films by Controlled Phase Transition of Blended Nanoparticle Building Blocks

Nanostructured composite thin films showing magnetic exchange coupling at the materials interface have attained high interest for the development of electronic components such as spin-valves. Besides the commonly performed fabrication of multilayer systems, the utilization of nanoparticle building blocks holds a great potential for thin films with tailored magnetic properties and allows the facile but controlled combination of materials with complementary magnetic characteristics. In this manuscript, we present the use of pre-fabricated highly crystalline iron platinum (fcc-FePt) and iron oxide (FexOy) nanoparticles for the preparation of nanocomposite thin films with varying compositions by wet processing from mixed dispersions. The resulting multiphase coatings showed high homogeneity, low surface roughness and superparamagnetic behavior. By variation of the amount of incorporated iron oxide, a precise adjustment of the magnetization at high field strength could be achieved. Furthermore, calcination und...