5 years ago

Building Composite Iron–Manganese Oxide Flowerlike Nanostructures: A Detailed Magnetic Study

Building Composite Iron–Manganese Oxide Flowerlike Nanostructures: A Detailed Magnetic Study
Sergio Lentijo-Mozo, Efisio Zuddas, Alberto Casu, Andrea Falqui, Davide Deiana
Here we show that it is possible to produce different magnetic core–multiple shell heterostructures from monodisperse Fe3O4 spherical magnetic seeds by finely controlling the amount of a manganese precursor and using, in a smart and simple way, a cation-exchange synthetic approach. In particular, by increasing the amount of precursor, we were able to produce nanostructures ranging from Fe3O4/manganese ferrite core–single-shell nanospheres to larger, flowerlike Fe3O4/manganese ferrite/Mn3O4 core–double-shell nanoparticles. We first demonstrate how formation of the initial thin manganese ferrite shell determines a dramatic reduction of the superficial disorder in the starting Fe3O4, bringing nanomagnets with lower hardness. Then, the growth of the second and most external manganese oxide shell causes magnetic hardening of the heterostructures, while its magnetic exchange coupling with the rest of the heterostructure can be either antiferromagentic or ferromagnetic, depending on the strength of the applied external magnetic field. This response is similar to that of an iron oxide–manganese oxide core–shell system but differs from what is observed in multiple-shell heterostructures. Finally, we report that the most external shell becomes magnetically irrelevant above the ferrimagnetic–paramagnetic transition of the manganese oxide, and the resulting magnetic behavior of the flowerlike structures is studied in depth.

Publisher URL: http://dx.doi.org/10.1021/acs.jpcc.7b04915

DOI: 10.1021/acs.jpcc.7b04915

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.