Magnetic layers

Fig. 7. Thermomagnetic recording, (a) A focused laser beam generates a thermal profile in the magnetic layer, (b) The coercive force in the layer is reduced and its magnetisation can be reversed by a small magnetic field, here 30 kA/m. At room temperature, the coercive force is high and the written domains are...

Overcoats are an integral part of thin-film disk structures. Their primary role is to provide wear protection. The most common overlayers, such as Rh, plasma-polymerized coatings, SiOz, and carbon, are all chemically stable if they were fully to cover the disk surface, they would provide good corrosion resistance. The thinness of the overcoats and the roughness of the surface preclude perfect coverage and open up the path for localized corrosion at the sites where the magnetic layer is exposed to the environment. 

Hattori et al. [140] investigated various overcoats for the thin sputtered y-Fe203 and plated CoNiP films. Rhodium overcoats exhibit defects caused by corrosive attack of the plating solution on the magnetic layer (prior to the corrosion test) ... 

Another surprise was that nuclear spins also become polarized by the magnetic layer after several minutes. This polarization acts like a magnetic field causing electron spin to precess at a frequency and in a direction controlled by the magnetic layer. 

Our choice of the metal for the 1 T magnet was silver. Cutting of the magnet layers from silver tubes was done by means of a specially designed, numerically controlled tooling machine (Fig. 6). Traditional tooling machines... 

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