Magnetic properties of Al, Ga, Sc, In substituted barium ferrites: A comparative analysis

Albanese, G.; Deriu, A.

doi:10.1016/0390-5519(79)90002-4

Cited by 77 publications

(22 citation statements)

References 8 publications

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“…We use the formation probability at 1000 K to compute the weighted averages as the crystalline configurations of SFAO will be distributed according to this value during the annealing process. Table IV shows that M s decreases as the concentration of Al x is increased from 0 to 0.5 to 1.0, consistent with the previous experimental results [1,20,40,41]. Our calculation also shows that K 1 decreases as the concentration of Al x is increased from 0 to 0.5 to 1.0.…”

Section: Configsupporting

confidence: 91%

Site occupancy and magnetic properties of Al-substituted M-type strontium hexaferrite

Dixit

Nandadasa

Kim

et al. 2015

Journal of Applied Physics

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We use first-principles total-energy calculations based on density functional theory to study the site occupancy and magnetic properties of Al-substituted M -type strontium hexaferrite SrFe12−xAlxO19 with x = 0.5 and x = 1.0. We find that the non-magnetic Al 3+ ions preferentially replace Fe 3+ ions at two of the majority spin sites, 2a and 12k, eliminating their positive contribution to the total magnetization causing the saturation magnetization Ms to be reduced as Al concentration x is increased. Our formation probability analysis further provides the explanation for increased magnetic anisotropy field when the fraction of Al is increased. Although Al 3+ ions preferentially occupy the 2a sites at a low temperature, the occupation probability of the 12k site increases with the rise of the temperature. At a typical annealing temperature (> 700 • C) Al 3+ ions are much more likely to occupy the 12k site than the 2a site. Although this causes the magnetocrystalline anisotropy K1 to be reduced slightly, the reduction in Ms is much more significant. Their combined effect causes the anisotropy field Ha to increase as the fraction of Al is increased, consistent with recent experimental measurements.[4] decreased coercivity. However, the coercivity of the M-type hexaferrites is not increased significantly by these cation substitutions, and is still much smaller than that of Nd-Fe-B magnet [15].Al substitution in the M-type hexaferrite has been more effective in enhancing coercivity [16][17][18][19][20]. Particularly, Wang et al synthesized Al-doped SFO SrFe 12−x Al x O 19 (SFAO) with Al content of x = 0 − 4 using glycinnitrate method and subsequent annealing in a temperature over 700 • C obtaining the largest coercivity of 17.570 kOe, which is much larger than that of SFO (5.356 kOe) and exceeds even the coercivity of the Nd 2 Fe 17 B (15.072 kOe) [1]. Wang and co-workers also observed that the coercivity of the SFAO increases with increasing Al concentration at a fixed annealing temperature. These results call for a systematic understanding, from first principles, of why certain combinations of dopants lead to particular results. This theoretical understanding will be essential in systematically tailoring the properties of SFO.

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Section: Configsupporting

confidence: 91%

Site occupancy and magnetic properties of Al-substituted M-type strontium hexaferrite

Dixit

Nandadasa

Kim

et al. 2015

Journal of Applied Physics

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“…Similarly, the addition of Ir and Co (as Co(x)/Ir(x)) reveals clear trends of increasing x reducing H A from >15kOe to <1.2 KOe to the point where for x>0.65 the H A is poorly defined and possibly aligned in the basal plane. [6] Li et al [7] in substituting Zn and Zr (as Zn(x/2)/Zr(x/2)) also found a pronounced reduction in H A from ~16 to <10 kOe. Daigle et al has experimented with the substitution of Co ions in both Y and Z hexaferrites as choice materials as antenna substrates for UHF to S band applications [8].…”

Section: The Effect Of Cation Substitution Upon Magnetic Anisotropymentioning

confidence: 91%

Tuning of Structure and Magnetic Anisotropy in Microwave Ferrites

Harris

Chen

et al. 2014

J. Jpn. Soc. Powder Powder Metallurgy

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The role of magnetic anisotropy and crystallographic texture in determining rf properties of ferrites, and their performance characteristics when integrated within high frequency devices, is explored. Both thin film epitaxial and bulk polycrystalline texture are discussed defining viable paths to realizing crystallographic texture required for device integration. Of the broad classes of ferrite, we focus much of our attention on the versatile hexaferrite materials systems.

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“…Further increase in the value of coercivity can be correlated to the effect of substituent particularly Al 3+ ions. Previously, it was reported that Al substituted M-type hexaferrite show large coercivities due to its ability to increase the anisotropy field [25,26]. On the other hand, the rare earth ions are also reported to increase the magneto crystalline anisotropy of the material [27].…”

Section: Magnetic Characterizationmentioning

confidence: 99%

W-type hexaferrite nanoparticles: A consideration for microwave attenuation at wide frequency band of 0.5–10GHz

Iqbal

Khan

Takeda³

et al. 2011

Journal of Alloys and Compounds

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Magnetic properties of Al, Ga, Sc, In substituted barium ferrites: A comparative analysis

Cited by 77 publications

References 8 publications

Site occupancy and magnetic properties of Al-substituted M-type strontium hexaferrite

Site occupancy and magnetic properties of Al-substituted M-type strontium hexaferrite

Tuning of Structure and Magnetic Anisotropy in Microwave Ferrites

W-type hexaferrite nanoparticles: A consideration for microwave attenuation at wide frequency band of 0.5–10GHz

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