X-ray diffraction studies on aluminum-substituted barium hexaferrite

Effect of Al-substitution on phase formation and magnetic properties of barium hexaferrite synthesized with sol-gel auto-combustion method

“…The decrease of H c is certainly due to crystallite size growth. In comparison with non-substitution barium ferrite, the increase in the coercivity and the decrease in the magnetization with Al-substitution barium ferrite are in agreement with the observation made for Al-substitution barium hexaferrite prepared by the hydrothermal precipitation-calcination techniques [23] . The observation confirms the formation of Al-substitution in barium ferrite in the present study.…”

“…Fig.2 shows the XRD pattern of Al-substituted asburnt powder and the powders annealed at 900 ℃, 1 000 ℃, 1 100 ℃, and 1 200 ℃ when x=0.5. As-burnt powder only contains barium carbonate and γ-Fe 2 O 3 , and no crystalline phase of aluminum is found in the XRD pattern, the conclusion is similar to [23]. Maybe the content of aluminum ions is too small.…”

Efficiency and purity control in the preparation of pure and/or aluminum-doped barium ferrites by hydrothermal methods using ferrous ions as reactants

“…The substituted ions can weaken the super-exchange between the two sub-lattices in the ferrimagnetic barium ferrite structure that causes the moments to align in an anti-parallel fashion. Aluminum-substituted barium hexaferrites synthesized by hydrothermal precipitation and calcination have been reported by Mishra et al [15]. However, samples calcined at 1200 1C by this method were found to contain significant amounts of a-Fe 2 O 3 impurity.…”

Preparation and characterisation of magnetically ordered columnar structures of barium ferrite particles

“…Surprisingly, in our case the M value decreased after firing. Comparing Figure 9(a) and (b), one can see the M (10 kOe) of the sample before firing (Figure 9(a)) is 36 emu/ g, while the M (10 kOe) of the same sample after firing (Figure 9(b) , which further results in a decrease of the M value [21]. We can also see in Figure 9(b) that the magnetisation of the fired sample does not saturate when it is measured parallel to the sample plane.…”

“…We can also see in Figure 9(b) that the magnetisation of the fired sample does not saturate when it is measured parallel to the sample plane. The reason for this is the high magnetocrystalline anisotropy field (17 kOe [1]) of the BaFe 12 O 19 itself, which is even higher after the incorporation of Al 3þ [21]. Since the majority of the particles are oriented with the easy magnetic axis perpendicular to the applied field, the maximum obtainable field of 10 kOe field is not enough to orient all the magnetic domains parallel to the applied field.…”