Nanocomposites formed by hard and soft magnetic phases are very promising for magnetic energy storage and biomedical applications. Highly challenging is the development of simple synthesis methods able to tune the phase composition and a thorough structural, morphologic and magnetic characterization in order to understand and optimize the interactions between hard and soft magnetic phases. Mainly depending on Fe:Pt atomic ratio, multi-phase or single phase FePt nanocomposites have been prepared by thermal treatment of core-shell FePt(Ag)@Fe3O4nanoparticles at 750 °C for 1 h under flow of a Ar + 5% H2gas mixture (H2is necessary to reduce Fe2+and Fe3+ions of Fe3O4to Fe0atoms and the thermal treatment to form the crystalline soft and hard magnetic FePt phases). Performing Rietveld refinement of the XRD data as well as HR-TEM and electron diffraction analyses, the different phases have been singled out. Besides single phase hard L10FePt and soft magnetic L12Fe3Pt nanoparticles, two phase soft α-FePt and γ-FePt and hard and soft magnetic L10FePt and L12FePt3nanocomposites have been formed and the structure and morphology correlated to their magnetic behavior. Moreover, for possible applications, it is important to form stable nanoparticle layers; as-prepared FePt(Ag)@Fe3O4nanoparticles have been chemically attached on a Si substrate, thermally annealed and the morphology, structure and magnetic properties of the layered nanoparticle sample investigated.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry