锶铁氧体矫顽力和剩磁增强的机理分析(英文)

Mechanism analyses of coercivity and remanence enhancement in strontium ferrites

通过改变前驱体溶液中Fe3+/Sr2+的摩尔比和烧结温度,用共沉淀法合成锶铁氧体的纳米晶体.由于应力各向异性的减弱,随着烧结温度的增加,单相和复合相的SrFe12O19纳米粒子样品的矫顽力均减小.对于前驱体溶液中不同Fe3+/Sr2+摩尔比形成的单相SrFe12O19,矫顽力的大小主要由Fe3+空位和反磁化核决定.单相SrFe12O19纳米粒子间交换相互作用和硬磁的SrFe12O19与软磁的γ-Fe2O3之间的交换弹簧作用,可导致剩磁增强.

Nanocrystalline strontium ferrites were synthesized by co-precipitation method with the different Fe3＋/Sr2＋ mole ratio in the precursor solution and calcinated at different temperatures.With increasing calcination temperature,the coercivity decreased for both single-phase and composite SrFe12O19 samples which can be assigned to the weakened stress anisotropy.For the single-phase SrFe12O19 samples with different Fe3＋/Sr2＋ mole ratios in the precursor solution,the coercivity was mainly determined by Fe3＋ vacancies and nuclei of reversed domain.The remanence enhancement was also observed,which can be attributed to the intergrain exchange interactions for single phase SrFe12O19 and to the exchange-spring for the composite of hard SrFe12O19 and soft γ-Fe2O3.