Computer Simulations of the Magnetic Properties of ${\rm Sm}-{\rm Co}/\alpha-{\rm Fe}$ Nanocomposite Magnets With a Core-Shell Structure

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

“…However, in spite of the potential strong role of the shape, there are only few theoretical studies devoted to hard-soft core/shell nanoparticles [105,107,226- 231]. Some simulations show that for hard/soft core/shell nanoparticles the evolution of H N on diverse parameters (e.g., shell thickness) follows quite closely the results expected from simple geometrical arguments (i.e., f hard /f soft ) [231].However, certain of these studies reveal, for example, large soft grains (in an inverse soft/hard structure) result in complex reversal or that the reduction of the interface coupling may enhance the spring-magnet type switching [228][229][230]. A recent systematic study of the effect of the hard/soft ratio for different nanoparticle sizes clearly evidences its important role on the magnetic properties (see Fig.…”

“…A recent systematic study of the effect of the hard/soft ratio for different nanoparticle sizes clearly evidences its important role on the magnetic properties (see Fig. 6a) [230]. In particular, it is shown that for each nanoparticle size the (BH) max is optimized for different hard/soft ratios (see Fig.…”

“…In particular, it is shown that for each nanoparticle size the (BH) max is optimized for different hard/soft ratios (see Fig. 6b), where for certain nanoparticle sizes very large (BH) max could be obtained with relatively small hard phase counterparts [230]. Interestingly, in the case of the SmCo-Fe system, using periodic boundary conditions, the conventional SmCo/Fe core/shell nanoparticles seem to have improved properties with respect to the inverse Fe/SmCo ones [230].…”

Magnetic properties of isotropic and anisotropic SmCo5/α-Fe nanocomposite magnets with a layered structure simulated by micromagnetic theory

“…9,10 It has been also reported that a Sm-Co/a-Fe multi-layered thick film-magnet has a small temperature coefficient of H c , approximately À0.3%/K. 11 These experimental results suggest the importance of Sm-Co/a-Fe multi-layered magnets, and the clarification of potential of a Sm-Co/a-Fe layered structure is needed for further investigations.…”

“…The detailed method of determining parameters at 473 K was also reported elsewhere. 11 The exchange constant J sh at the interface between Nd 2 Fe 14 B and a-Fe was assumed to be 1.6 Â 10 À3 J/m 2 , 13 and…”