Magnetocrystalline anisotropy of La- and Co-substituted M -type strontium ferrites: Role of Co2+ and Fe<

Abstract

We have systematically investigated magnetic properties of La and Co substituted SrFe12O19 using single crystals. By utilizing travelling solvent floating zone technique, we have grown single crystals over wide range of substitution content, and examined their saturation moments and magnetocrystalline anisotropy. With increasing content of La and Co, saturation moment at 300 K monotonically increases. The increment of magnetocrystalline anisotropy is almost proportional to the content of Co. In addition, further La substitution also enhances magnetocrystalline anisotropy, which demonstrates that Fe 2+ plays an important role to enhance magnetocrystalline anisotropy. We have analyzed magnetocrystalline anisotropy energy as a function of substitution content, and elucidate the effects of Co 2+ and Fe 2+ .

Direct imaging of dopant sites in rare-earth element-doped permanent magnet and correlated magnetism origin

“…It has been reported that the magneto-crystalline anisotropy and coercive field of M-type strontium hexaferrite can be increased or reduced according to the concentrations of the substituted La 3+ cations. [20][21][22][23] Fe or Sr lattice sites are argued to be the strong preference for the La 3+ substitutions, which are thought to be responsible for the intrinsic physical mechanism of mag-netism modulation. Many efforts using the abovementioned techniques have been devoted to confirming the site preference of the substituted ions in M-type strontium hexaferrite.…”

An ab initio study of the magnetic properties of strontium hexaferrite

“…Still, important properties such as the electronic gap have not yet been determined. In the last 2 decades, significant effort has been devoted to improve its magnetic performance, particularly for permanent magnet applications, by chemical substitution and nanostructuring [3][4][5][6][7] . Nanometric thin SFO platelets have been recently characterized combining fundamental experimental techniques, as X-ray absortion based and Mössbauer spectroscopies, to density functional theory (DFT) calculations intended to rationalize Oxygen K absortion edge spectrum measurements 8 .…”

Synthesis, Magnetic and Electrical Characteristics of Ba‐Sr Hexaferrites Substituted with Samarium, Chromium and Aluminum

“…The internal crystal structure of M‐type ferrite can be changed by ion substitution, which makes the lattice constant, magnetocrystalline anisotropy and total magnetic moment change. The ion substitution of M‐type ferrite mainly includes three aspects: (1) the ion substitution for Me 2+ ions, [7–13] (2) the ion substitution for Fe 3+ ions, [14–21] and (3) the joint substitution of ions [22–33] . Roy et al [10] .…”

“…The ion substitution of M-type ferrite mainly includes three aspects: (1) the ion substitution for Me 2 + ions, [7][8][9][10][11][12][13] (2) the ion substitution for Fe 3 + ions, [14][15][16][17][18][19][20][21] and (3) the joint substitution of ions. [22][23][24][25][26][27][28][29][30][31][32][33] Roy et al [10] synthesized LaÀ Sm substituted strontium ferrites SrAl 4 (La 0.5 Sm 0.5 ) x Fe 8-x O 19 (0 � x � 1.5) by spontaneous combustion method, and found that with the increase of LaÀ Sm substitution amount, B r increased, while H cj decreased and when x = 1.0, the optimized properties were B r = 5.19 kg, H cj = 6.18 kOe, (BH) max = 6.69 MGOe and T c = 492 K. Trusov et al [22] studied the strontium hexagonal ferrite prepared by using the citrate melt autoignition method, and found that the H c reach the giant value of 21.3 kOe at M s of 14 emu/g, this effect is due to the increase of magnetocrystalline anisotropy caused by the distortion of crystal structure. Mishra et al [25] studied the magnetic properties of M-type ferrites SrFe 12-x Cu x O 19 and Sr 1-x La x Fe 12-x Cu x O 19 , and found that the presence of La 3 + increased the values of M s and H c , but the lattice distortion caused by La 3 + substitution reduced the value of T c , the enhancement of the hyperfine field value of 12k crystal site by La 3 + -Cu 2 + co-substitution made M s higher than that of SrM replaced by Cu 2 + .…”