This chapter is dedicated to the analysis of the spin resonance response (ESR) of different magnetic phases, in nanoparticles (NPs) of magnetic oxides, or ferrites. Evidence of the correlations between resonance spectrum and magnetic structure has been published, of course, in many works; however, to our knowledge, it is somewhat scattered and not easily accessible. We have chosen to carry out this analysis mainly on ferrite NPs because these magnetic materials exhibit a wide variety of magnetic properties, and as a consequence, a large diversity of classic and novel applications in technological fields ranging from electronics to biomedics.
Part of the book: Advanced Electromagnetic Waves
Ferrites are a well-known class of ferrimagnetic materials. In the form of nanoparticles (NPs), they exhibit novel and fascinating properties, leading to an extremely wide variety of applications in electronics, biomedical and environmental fields. These applications result from nanoscale effects on physical properties, particularly magnetic properties. For applications in electronic devices, however, a high-density, consolidated body, with very fine grains is needed, in order to retain the nanoscale properties. To our knowledge, spark plasma sintering (SPS) is the only method permitting a full densification with final grain size in the nanometer range. In this review, we examine the SPS method as applied to ferrites and, in particular, the effects of SPS parameters on the final nanostructures obtained. Due to their technological impact, we also discuss the SPS fabrication of hybrid multiferroic nanostructures composed of a ferrite and a ferroelectric phase.
Part of the book: Nanostructured Materials
A wide variety of technological applications, especially in electronics, requires high‐density nanostructured solids, consolidated by sintering from nanoparticles. A new sintering technique known as spark plasma sintering (SPS) appears as the only method to reach high densities while preserving the final grain size within the nanometric range, with the added advantage of carrying out the process at significantly lower temperatures and shorter times as compared with the classical processes. Recent studies have revealed that in many cases, SPS can also accomplish the solid‐state reaction to achieve the desired compound, leading to reactive SPS (RSPS). In this chapter, a review of RSPS is presented, focusing particularly on magnetic oxide materials as functional solids.
Part of the book: Sintering of Functional Materials