Claudio Sangregorio

Abstract:

Currently, there is a rising demand for rare-earth (RE) elements for a broad range of industrial applications. However, the risk of supply of these strategic materials due to political restrictions, the high environmental impact of their extraction as well as price oscillations have motivated many researchers in finding viable alternatives. Specifically, in the case of permanent magnet applications, the research is focusing on finding novel materials that can replace currently used RE permanent magnet in a wide part of the spectrum of industrial necessities where the high performance of RE permanent magnets is not strictly required. In this contribution, we discuss the potentiality of ferrite NPs to achieve this goal. In particular, we will focus on cobalt ferrite nanoparticles (NPs) with average size covering a broad range (from 4 to 60 nm) synthesized by thermal decomposition of metal-organic precursors. We will show how the fine tuning of morphological, structural and chemical features may strongly increase their (BH)max product, which is the figure of merit of permanent magnets. The possibility of further improvement of the nanomaterial performance by orienting the nanocrystals or coating the hard core with a soft ferrite (exchange coupled core/shell nanoparticles) will be also discussed. Research supported by EU-FP7 NANOPYME Project (No. 310516) [www.nanopyme-project.eu]