Sc-doped barium hexaferrite nanodiscs: Tuning morphology and magnetic properties
Hähsler, M. / Zimmermann, M. / Heißler, S. / Behrens, S. (2020)
Journal of Magnetism and Magnetic Materials, 2020, 500, doi: org/10.1016/j.jmmm.2019.166349166349
- Datum: Dezember 2019
Magnetic nanoparticles exhibit size- and shape-dependent magneticproperties[1,2]and have attracted great interest for a variety of ap-plications, including catalysis[3,4], magneto-optics[5,6]or magneticseparation of enantiomers. The synthesis and application of nano-particles consisting of various magnetic materials have been reported,including ferrites (in particular spinel-type ferrites, e.g. Fe3O4,CoFe2O4), metals (e.g. Co, Fe) and alloys (e.g. FePt) while the synthesisof defined nanosized particles of the hexaferrites has remained scarce[8–11]. Hexaferrites possess a hexagonal crystal structure with closepacking of oxygen ion layers. Trivalent metal cations are located ininterstitial sites of the structure while the heavy ions (e.g. Ba2+) entersubstitutionally the oxygen layers. Several types are known dependingon their chemical and crystalline structure. Hexagonal ferrites of the M-type such as BaFe12O19, are of enormous technical importance, e.g. aspermanent magnets due to their low cost, hard magnetic properties andstability in air[12,13]. Bulk BaFe12O19exhibits a saturation magneti-zationMsof 72 Am2/kg at room temperaturetogether with a re-latively high magnetocrystalline anisotropy (i.e. anisotropic constant33 × 104J/m3) and a Curie temperatureTcof 740 K.