Multiferroic Properties of Pure, Transition‐Metal and Rare‐Earth–Doped BaFe₁₂O₁₉ Nanoparticles

Abstract

Different properties of pure and Ni, Zr, and Sm‐doped BaFe12O19—bulk and nanoparticles—are investigated using a microscopic model and the Green's function technique. The magnetization Mnormals increases whereas the coercive field Hnormalc decreases with increasing particle size. The doping leads to a decrease of Ms and the bandgap energy Eg with increasing Zr concentration x due to tensile strain and to an increase of Ms and Eg after Ni doping due to compressive strain as well as due to size effects. The behavior of the spontaneous polarization Ps and the real part ϵ′ of the dielectric constant is opposite. The ϵ′ of a pure BaFe12normalO19 nanoparticle decreases with increasing magnetic field h. The effects of Sm substitution at Ba or Fe sites on ϵ′ and Ms are also studied.

Theoretical Study of Electric, Dielectric, and Optical Properties in Ion Doped Multiferroic SrFe12O19 Nanoparticles

“…It is noteworthy to mention that in our previous study [35], we investigated the multiferroic properties of both pure and ion-doped BFO, specifically incorporating Ni, Zr, and Sm dopants. To the best of our knowledge, there is a dearth of theoretical studies that have systematically examined the properties of ion-doped SFO, while there exist some investigations focusing on pure bulk SFO utilizing Density Functional Theory (DFT) techniques [8,36], comprehensive theoretical analyses regarding doped SFO remain scarce.…”

Coercivity, Activation Volumes, and Interactions in BaFe12O19

“…The commercial importance of M hexaferrites is related to their use not only as permanent magnets, but also in microwave devices, memories with high storage density and an increased importance in relation to magnetoelectric properties. [8][9][10][11][12][13] Despite these novel properties, in M hexaferrites there are open issues associated to mechanisms of magnetization reversal and magnetic relaxation. [14][15][16] As the grain size is reduced and multidomain state becomes unfavorable, magnetization reversal must occur by coherent or incoherent processes and therefore aspects such as interparticle interactions come to be more important.…”