Preparation and Magnetic Properties of Nd–Co-Substituted M-Type Strontium Ferrite by Microwave-Assisted Synthesis Method

Abstract

M-strontium hexaferrites (Sr 1−x Nd x Fe y Co 1−y O 19 ) with the substitution of Co 2+ and Nd 3+ were prepared by the microwave-assisted solid-phase reaction process. Mstrontium hexaferrite with magnetoplumbite structure can be formed at 950 • C for 90 min by applying microwaveassisted calcination. For Co 2+ -substituted M-strontium ferrites, the saturation magnetization (σ s ) and remanent magnetization (σ r ) tend to decrease with the increasing calcination temperature, accompanying by the improvement of coercivity for the enhancement of morphology anisotropy. For Nd-Co-co-substituted strontium ferrites, the appearance of α-Fe 2 O 3 phase and the conversion of Fe 3+ (5 μB) into Fe 2+ (4 μB) decrease the net magnetic moment, resulting in the dilution of the σ s and σ r . The coercivity of NdCo-co-substituted strontium ferrite increases slightly for the improvement of magnetocrystalline anisotropy, which could be attributed to the enhancement of anisotropy field for the substitution of Fe 3+ ions by Co 2+ ions and the formation of grains with plate-like shape.

Effect of Cr3+ doped on electronic and magnetic properties of SrFe12O19 by first-principles study

“…Nd [9], La [10,11], Pr [12], Zn-Sn [13], Sn-Mg [3], Er-Ni [2], Bi-Cr [14], Nd-Co [15], Al [5], Ce-Zn [16] and Co [17]. However, there are few first-principles studies on doped SrFe 12 O 19 : in 2003, Fang et al [18] investigated the magnetic and electronic properties of SFO from first-principles calculations, and their calculations showed that the most stable state of the hexaferrite is a ferrimagnetic order with the Fe 3+ ions at the 4f sites having their magnetic moment anti-parallel to the rest of the Fe 3+ ions such as Gorter's prediction [19,20].…”