In this paper, we report the fabrication and characterization of two kinds of mediums for magnetically induced
superresolution (MSR) and blue wavelength magneto-optical data storage. Both NdGdFeCo/TbFeCo and Pt<sub>3</sub>Co/TbFeCo
exchange coupled double layer structures show good MSR effect. At room temperature (RT), NdGdFeCo and Pt<sub>3</sub>Co
have in-plane magnetization, however, with temperature rising, they become out-of-plane magnetized and copy the bit
information of TbFeCo because of strong exchange coupling. This suggests that both of the double layer films are good
candidates for MSR/blue wavelength magneto-optical data storage.
We designed and built up an apparatus for measuring the properties of magnetic coupling thin films and hybrid recording media. The temperature of the tested points of the thin film samples change as irradiated by focused laser beam through adjusting laser power. By calculation, we also simulated the distribution of temperature in TbFeCo magneto-optical films irradiated by laser, in order to get the relationship between the film coercive force and the irradiating laser power. Using this apparatus, we can determine the Curie temperature and compensation temperature of the films. The apparatus might present an effective approach for studying the variation of magneto-optical characteristics of films at different temperatures and the properties of magnetic coupling multilayer films, and it could
be useful for studying hybrid recording.
The use of magnetic capping effect can enhance the head sensitivity of the heat assisted magnetic recording (HAMR). The principle of this effect was analyzed theoretically. The GdFeCo film was used as the capping layer and TbFeCo film was used as the recording layer. Through theoretical calculation we found that a large capping field in the same direction with the external field can be generated at the interface because of the exchange coupling effect, which had increased the effective strength of the external field. Thus, the head sensitivity was improved greatly and the data transfer rate could be faster. We expected that this idea can be used to help write the medium with much larger cocervity such as L1<sub>0</sub>FePt.
The conventional TbFeCo magneto-optical medium has a relatively smaller kerr rotation angle in blue region than in the red. Consequently, intensive optimization of the RE-TM blue disk is needed. In this paper, optimization of magneto-optical properties and optical properties was carried out, and good results were obtained. We also calculated the temperature distribution of the recording layer, the results showed that the newly designed structure was successful in temperature controlling and had better thermal response.
The Bi<sub>1</sub>Dy<sub>2</sub>Fe<sub>4.3</sub>Al<sub>0.7</sub>O<sub>12</sub> films with perpendicular anisotropy were successfully prepared by citric acid complex type sol-gel method. The properties of Bi-substituted garnet films annealed at different temperatures were investigated. The results indicated the garnet films had high squareness. The coercive force of the films was about 1100 Oe. The figures of merit of 2° at 430 nm and 1.5° at 520 nm were obtained. The best crystallization temperature was 650°C.
In this paper AgO<sub>x</sub> films for super resolution near-field structure application were prepared by reactive sputtering. The switching properties of AgO<sub>x</sub> films were studied by analyzing the relationship between the transmittance and the laser power. We gained results that AgO<sub>x</sub> films had excellent switching properties and the reaction (formula available in paper) was reversible. The structures of AgO<sub>x</sub> films were investigated by X-ray diffraction and TEM.