Synthesis and characterization of SrFe12O19/CoFe2O4 nanocomposites with core-shell structure

Applications of exchange coupled bi-magnetic hard/soft and soft/hard magnetic core/shell nanoparticles

“…When analyzing the magnetic properties observed experimentally for diverse hard-soft core/shell nanoparticles a spread of different behaviors can be found [91][92][93][94][95][98][99][100][102][103][104]106,107,110,111,114,115,[121][122][123][125][126][127][128][129][130][131][132]136,140,141,143,175,. First, it should be pointed out that given that we are dealing with nanoparticles the core and shell sizes are rather small (i.e., usually smaller than 2 H ), thus, most of the systems exhibit smooth hysteresis loops typical of strongly exchange coupled hard-soft counterparts.…”

“…13). Experimentally, a number of studies concerning the control of the microwave properties in different types of hard/soft systems (i.e., thin films, nanocomposites and core/shell nanoparticles) can be found in the literature [45,91,123,124,129,270,271,294,[342][343][344][345][346][347][348][349][350][351][352][353][354][355]. Many studies show that µ' and µ'' depend on the ratio of hard/soft materials both for core/shell nanoparticles [129,342,345], nanocomposites [45,[347][348][349][350][351][352] and bilayers [354].…”

“…Studies on both hard-soft core/shell nanoparticles and nanocomposites have demonstrated that the main parameters of R L can be controlled by the hard/soft ratio [45,91,123,129,271,294,[342][343][344][345][346][347][348][349][350][351][352].…”

“…Diverse types of systems have been studied, based on different hard magnetic materials, e.g. CoFe 2 O 4 [123,124,129], hexagonal ferrites (e.g., Sr-ferrite or Ba-ferrite) or more novel materials such as Fe 16 N 2 [91,270,271,[342][343][344][345][346]. Moreover, the patents on core/shell nanoparticles and the studies on nanocomposite materials (i.e., not core/shell) have also shown that other hard materials may be potentially interesting as reflection loss materials, e.g.…”

“…FeNdN [82] and FeNdB [351]. The different core/shell systems have shown advances in diverse aspects of reflection loss: increase in R L [91,124,129,270,271,294,342,[344][345][346] (see Fig. 19), higher working frequencies [124,271,294] or improved bandwidths [91,344,345].…”