Magneto-optical properties and thermomagnetic recording of M-type Ba-ferrites

Machida, Hideo; Ohmi, F.; Sawada, Y.; Kaneko, Yoshiki; Watada, Atsuyuki; Nakamura, Hakobu

doi:10.1016/0304-8853(86)90870-x

Cited by 38 publications

(7 citation statements)

References 3 publications

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“…The MO enhancement factors of the Ni 2+ ions at 2b and 4f 1 sites are near the observed values [9]. According to Machida et al [3] and Gomi et al [9], the Faraday rotation induced by a Fe 3+ ion in the barium ferrite is much smaller than that by a Ni 2+ ion at the 2b or 4f 1 site. Therefore, in explaining the enhancement by Ni 2+ substitution, it has been neglected to a first-order approximation.…”

Section: Full Faraday Rotation and The Influence Of The Mixing Of Difmentioning

confidence: 49%

“…Obviously, θ F (ng) is given by one term on the right side of equation (4). We would like to recall that equations (3,4) stand only when the optical absorption is weak. Therefore, at high photon energy, θ F (ng) should be read as 1 9 (n 2 + 2) 2 π λn ε xy .…”

Section: "Paramagnetic Type" Faraday Rotationmentioning

confidence: 99%

“…However, some properties of these materials are still less than satisfactory. With new techniques developed to prepare garnets and ferrite thin films [1][2][3][4], magnetic oxides again become potential candidates for the MO recording material. While oxide thin films are able to overcome some of the major deficiencies of the rare-earth transition-metal alloy films, some properties of these materials, e.g., the uniaxial anisotropy, the coercivity, the grain size, and the high crystallization temperature, require further improvement for the MO recording application.…”

Section: Introductionmentioning

confidence: 99%

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Quantum theory of the magneto-optical effect induced by Ni ions in barium ferrites

Zhang

Guillot

1999

Eur. Phys. J. B

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To reveal the physical origin of the giant magneto-optical enhancement of Ni 2+ ions in barium ferrite, quantitative calculations of the contributions of both the intra-ionic electric dipole transition between the 3d 8 and 3d 7 4p configurations of the Ni 2+ ions and the intra-ionic electric dipole d → d transition induced by odd-parity crystal field terms are presented. It is deduced that the 3d 8 → 3d 7 4p transition is important in the origin of the considered magneto-optical enhancement. The most important factor is the Ni-Fe superexchange interaction; since it is strong enough, the Faraday rotation produced by the Ni 2+ ions is large though the energy difference between the 3d 8 and 3d 7 4p configurations is large. It is demonstrated that though the intra-ionic electric dipole d → d transition does produce Faraday rotation peaks in the visible range, their magnitude is too small to explain the observed Faraday rotation. The effect of the spin-orbit interaction on the Faraday rotation is analysed. The spin-orbit interaction of the ground configuration plays a very important role in the occurrence of Faraday effects, but the Faraday rotation does not increase linearly with the strength of the spin-orbit coupling. On the contrary, the spin-orbit interaction of the excited configuration has almost no effect on the Faraday rotation. It is shown that the mixing of the different multiplets of the ground term induced by the crystal field has a great influence on the magneto-optical properties.

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Section: Full Faraday Rotation and The Influence Of The Mixing Of Difmentioning

confidence: 49%

Section: "Paramagnetic Type" Faraday Rotationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quantum theory of the magneto-optical effect induced by Ni ions in barium ferrites

Zhang

Guillot

1999

Eur. Phys. J. B

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“…BaTi sample) modifies the almost constant Kerr rotation values of BaM into the spectral dependent curve that reminds PKR behaviour of magnetite [7][8][9]. Also the introduction of cobalt induces new spectral features that are complementary to those observed in the Faraday rotation spectra of Co-Ti-substituted hexaferrite platelets [3] or thin films [10][11][12]. In contrast to the unusually large PKR values (about 1 degree) obtained on the flux grown single crystals earlier [2] the present local extrema observed at photon energies of about 0.7, 0.9 and 1.7 eV (Le.…”

Section: Resultsmentioning

confidence: 99%

Optical Reflection and Polar Kerr Rotation of Cobalt and Titanium Substituted Barium Hexaferrites

1996

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-Optical reflection and the polar Kerr rotation of four single crystals of barium hexagonal ferrites were measured in the visible and near infrared region at room temperature. Local extrema of the polar Kerr rotation at wavelengths of 1650, 1350 and 760 nm could be assigned to the presence of Co2+ in tetrahedral positions. The figure of merit attains the maximum values at these wavelengths suggesting material to be suitable for the magneto-optical storage applications.

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“…situation is slightly more complicated due to the presence of Ce3+, Ce4+ and Fe 2 + ions where the latter are distributed over the tetrahedral and octahedral sites [38]. Co-based spinel ferrites [11,39] and hexagonal barium ferrites [40,41] also have been investigated for magneto-optical recording. They exhibit no Tcomp.…”

Section: Magnetization Curie Temperature and Compensation Temperaturementioning

confidence: 99%

Garnets and Ferrites for Magneto-Optical Recording

1991

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-The present contribution reviews the current status of ferrirnagnetic oxides for magneto-optical recording where special attention is paid to iron garnet fi1.ms deposited by pyrolysis and sputtering. The magnetic and magneto-optical properties are discussed. The influence of the preparation conditions and the annealing treatments controlling microstructure, grain size and homogeneity of the films are analyzed with respect to their relevance to structure-sensitive quantities such as coercivity, noise and other recording parameters determining the performance of magneto-optical disks.

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Magneto-optical properties and thermomagnetic recording of M-type Ba-ferrites

Cited by 38 publications

References 3 publications

Quantum theory of the magneto-optical effect induced by Ni ions in barium ferrites

Quantum theory of the magneto-optical effect induced by Ni ions in barium ferrites

Optical Reflection and Polar Kerr Rotation of Cobalt and Titanium Substituted Barium Hexaferrites

Garnets and Ferrites for Magneto-Optical Recording

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