Efficient hysteresis loop simulations of nanoparticle assemblies beyond the uniaxial anisotropy

Quantifying magnetic anisotropy dispersion: Theoretical and experimental study of the magnetic properties of anisotropic FeCuNbSiB ferromagnetic films

“…The more general anisotropic case has been also received attention and several very interesting works on this issue can be found in literature. This is the case of studies on the influence of the function f (ψ) on the magnetic parameters of the magnetization curve [22,23], description of systems with biaxial anisotropy [29,30], with distribution of magnetic moment of particles [31] or of anisotropy strength [24,25,32,33], as well as investigations of systems considering interactions between the particles through a mean field [24,25,[34][35][36][37] or taking into account temperature effects [38][39][40][41]. On the other hand, just a few studies compare numerical calculations and experimental results, probably due to the fact that the determination of the appropriate magnetic free energy density can represent a hard task.…”

Anisotropy evolution of nanoparticles under annealing: Benefits of isothermal remanent magnetization simulation

“…The consideration of a low temperature IRM curve extends the so-called "triple fit" approach, [8] already successful in the characterization of nanoparticle assemblies, to a "quadruple fit" procedure even more discriminating. Moreover, the simulation of a low temperature hysteresis loop with the best fit parameters can also be performed [30] to verify the good agreement with experimental measurements.…”

Intrinsic magnetic properties of bimetallic nanoparticles elaborated by cluster beam deposition

“…It is probably the reason why the MAE of chemically disordered CoPt particles is quite large even if mass-selected clusters have small size dispersion (8% determined by TEM). To go further, the hysteresis loops at 2 K have been fitted using a geometrical approach 27,28,29 . Upon annealing, as long as a well-defined and high enough degree of chemical order can be reached, the multiplicity of atomic configurations is strongly reduced and the effective MAE dispersion is expected to decrease while its median value increases 26 .…”

“…Concerning the binary bulk phase diagram, the FeCo system is characterized by an extensive solid solution range between fcc Fe and fcc Co and a wide bcc-Fe solid solution region which transforms via a second order reaction into the ordered CsCl type phase FeCo (see Fig. Simultaneous fitting of the ZFC-FC curves and the hysteresis M(H) with the triple-fit protocol 21 shows an enhancement of the MAE after annealing almost doubles as seen Table III In addition, X-ray magnetic circular dichroism (XMCD) measurements were performed on these samples at both Co and Fe L 2,3 edges on the DEIMOS beamline at SOLEIL (France). Recent theoretical advances predicted that structural distortion in FeCo nanoalloys in chemically ordered B2 phases can lead to a giant MAE together with a large M s (see Fig.…”