Directed Assembly of BaFe₁₂O₁₉ Particles and the Formation of Magnetically Oriented Films

Abstract

We have studied the preparation of oriented BaFe(12)O(19) films produced using electrophoretic deposition (EPD). Highly anisotropic, platelike BaFe(12)O(19) particles were synthesized under hydrothermal conditions, and from these particles, stable suspensions were prepared in 1-butanol by the addition of dodecylbenzene sulfonic acid as a surfactant. The interplay of the interaction forces between the suspended particles and the forces acting on the particles during the EPD directed the particles' assembly in the plane of the substrate. The most significant effect on the orientation of the films was the diameter-to-thickness ratio of the particles, which was experimentally confirmed with X-ray analyses, electron microscopy, and magnetic measurements. The abnormal grain growth that accompanied the sintering at 1150 °C further improved the overall orientation of the films, which showed highly anisotropic magnetic behavior with a remanent-to-saturation magnetization ratio exceeding 0.8.

Monolithic Magneto-Optical Nanocomposites of Barium Hexaferrite Platelets in PMMA

“…The selected-area electron diffraction (SAED; see Supplementary, inset in Figure S1a) indicates the barium hexaferrite structure with intense hk0 diffraction rings since the platelets were preferentially aligned in the plane of the supporting grid. These nanoparticles exhibit a room-temperature magnetization of 32 emu g −1 (measured at 1 kOe) and a coercivity of 1250 Oe.The preparation of a stable suspension comprising these particles, which was achieved with the electrosteric stabilization of the BaHF nanoparticles in 1-butanol26. Monodomain BaHF nanoparticles, dispersed in 1-butanol, were already sensitive to a weak magnetic field.…”

“…The preparation of a stable suspension comprising these particles, which was achieved with the electrosteric stabilization of the BaHF nanoparticles in 1-butanol26. Monodomain BaHF nanoparticles, dispersed in 1-butanol, were already sensitive to a weak magnetic field.…”

“…BaHF nanoparticles with the nominal composition BaSc 0.5 Fe 11.5 O 12 were synthesized hydrothermally and dispersed in 1-butanol using the electrosteric repulsion of the surfactant dodecylbenzene sulphonic acid (DBSa)26. In brief, Ba, Fe and Sc nitrates in the atomic ratio Ba:Fe:Sc = 1:4.5:0.5 were dissolved in water and co-precipitated with NaOH.…”

Magnetically controllable random laser in ferromagnetic nematic liquid crystals

“…Sc-substituted barium hexaferrite nanoparticles were synthesized hydrothermally and dispersed in 1-butanol using dodecylbenzenesulfonic acid as previously in Ref. [31]. A suspension of 0.6 wt% MNPs in 1-butanol was mixed with DNLCs, where the concentration of MNPs was 0.1 wt%.…”

M-SrFe 12 O 19 and ferrihydrite-like ultrathin nanoplatelets as building blocks for permanent magnets: HAADF-STEM study and magnetic properties

“…Furthermore, the self-assembly properties of platelets were also exploited in different studies. BaFe 12 O 19 thin platelets were used as building blocks to form oriented films with highly anisotropic magnetic behavior by electrophoretic deposition [13]. Ferrofluids with very small BaFe 12 O 19 platelets were obtained using oleic acid as stabilizing agent [14] and field dependent optical properties were described on colloidal with a very high degree of alignment, even in absence of any applied magnetic field, and consequently provide high energy products [17].…”