Tuning the morphology and magnetic properties of single-domain SrFe8Al4O19 particles prepared by a citrate auto-combustion method

High-coercivity hexaferrite ceramics featuring sub-terahertz ferromagnetic resonance

“…The aluminum substitution leads to a drop of the saturation magnetization followed by a moderate reduction of K 1 , which results in an increase of the single domain size limit. 11,74 The estimated value of D C for Sr 0.67 Ca 0.33 Fe 8 Al 4 O 19 is about 8 μm; 11 however, this calculation does not consider grain shape and possible intergranular interactions. According to SEM (Fig.…”

In situ annealing achieves an ultrafast synthesis of high coercive strontium ferrite foams and beyond

“…4c). 4,18,[32][33][34][45][46][47][48][49][50] In addition, we also prove the generality of this method in the ultrafast preparation of porous oxide foams. In this respect, we successfully prepared a series of spinel-based and perovskite-based oxide foams with hierarchical porous morphologies (Fig.…”

“…4a). Because of the complex crystal structure, the 4,18,[32][33][34][45][46][47][48][49][50] strontium ferrite cannot be formed at the in situ annealing time of 0 s and 10 s. When increasing the in situ annealing time to 20 s, 40 s, 1 min, and 5 min, the M-type strontium ferrites can be obtained and their half-peak width decreases gradually (Fig. 4a).…”

“…(a) XRD patterns and (b) hysteresis loops of the Sr 0.94 Y 0.06 Fe 7 Al 5 O 19 foams obtained at 1500 °C for different in situ annealing time. (c) Comparison of the coercivity of strontium ferrites between this work and the reported studies 4,18,[32][33][34][45][46][47][48][49][50].…”

Glass-Ceramic Synthesis of Cr-Substituted Strontium Hexaferrite Nanoparticles with Enhanced Coercivity

“…Typical reported colloidal hexaferrite nanoparticles with diameters of 10-100 nm display coercivity values between zero and 360 kA m −1 (4500 Oe) for the largest particles [7,15,[22][23][24]. A common way to increase the coercivity of the hexaferrites is the partial substitution of iron ions with aluminum [1,3,21,[25][26][27], e.g., this can result in a coercivity of submicron single-domain particles of up to 3180 kA m −1 (40 kOe) [25]. However, the aluminum substitution requires high annealing temperatures above 1000 • C, which makes the preparation of nanoparticles quite challenging.…”