Below-diffraction-limited hybrid recording using silicon thin film super-resolution structure

We report on new experimental results forbelow-diffraction-limited hybrid recording. In our experiments, bymeans of focused laser assisted magnetic recording, the magneticdomains within TbFeCo thin films are obtained under an externalperpendicular direct magnetic field. For a single magnetic medium,the domain size is mainly determined by the focused spot, which isabout 620~nm for the laser wavelength λ =406~nm, anda numerical aperture of the lens of 0.80. However, when a silicon thinfilm structure is inserted between the substrate and the magnetic medium,the recording domains can be reduced obviously. By optimizing theexperimental condition, even the size can be reduced to about100~nm, which is below the diffraction limit, i.e. about 1/6 of the spotsize. This is very useful for improving the hybrid recording densityin practical applications.