Submicron particles of Ga-substituted strontium hexaferrite obtained by a citrate auto-combustion method

Abstract

In this study, we demonstrate the synthesis and the investigation of the magnetostatic and magnetodynamic properties of single-domain gallium substituted strontium M-type hexaferrite particles SrFe12-xGaxO19 (x = 1 - 6)....

High-coercivity hexaferrite ceramics featuring sub-terahertz ferromagnetic resonance

“…[13][14][15] and display the absorption of electromagnetic radiation in a high-frequency range of 1-250 GHz due to ferromagnetic resonance (FMR). 3,11,13,[15][16][17][18][19][20][21][22] The latter is particularly important for the development of wireless communication technologies. In the next decade, the fifth generation (5G) wireless technology operating at frequencies up to 100 GHz is expected to become widespread around the world.…”

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].…”

“…[41][42][43][44] As a kind of sol-gel process, auto-combustion is an ideal method to prepare Al 3+ -substituted strontium ferrite materials. 45,46 Surprisingly, the strontium ferrite foams obtained from the auto-combustion method possess a hierarchical porous structure, which can disperse the grains and further inhibit the agglomeration of grains during the annealing process. However, the preparation of high-coercivity strontium ferrites often requires long-time annealing at high temperatures, which greatly reduces the production efficiency of the materials.…”