Anisotropy of hexagonal ferrites with M, W and Y structures containing Fe3+ and Fe2+ as magnetic ions

✍ Scribed by F.K. Lotgering; P.R. Locher; R.P. van Stapele

• Publisher: Elsevier Science
• Year: 1980
• Tongue: English
• Weight: 887 KB
• Volume: 41
• Category: Article
• ISSN: 0022-3697
• DOI: 10.1016/0022-3697(80)90178-x

✦ Synopsis

Ahntrad-The ferrimagnetic saturation moment and hexagonal anisotropy constant K, have been measured at 4K on a Zn,Y single crystal and on ~Iycrystalline BaFe:' W and SrFei' W samples. The moment of Fe, Wis in agreement with a collinear spin coupling and with the known site occupation for the Fe2 + ions. The moment of Zn,Y is 9% lower than the value for a collinear configuration.

The uniaxial anisotropy of Fezin hexagonal ferrites is discussed and compared with that of Co". No noticeable Fe'* anisotropy is found in Fe,&' in contrast to LaM = LaFe' * Fe:; O's, in which the Fe2 ' anisotropy is strong. The difference is attributed to the symmetry difference of the sites occupied by the Fe* * ions in both compounds. The current theory does not satisfactorily explain the anisotropy and quadrupole splitting of Fe" in La&f. From this it is concluded that admixing of 'E states and (or) the influence of a dynamical Jahn-Teller effect cannot be neglected.

The dipole-dipole anisotropy is computed for the M, Wand Y structure and some deviation from the literature data is found. UsinR these results, a mean anisotropy of 1.3 to 2.3 cm -f per Fe3' ion is found for the three structures.