SiO2 substrate having self organized nanoscale pores and Co dot array on it and coercivity enhancement in RE-TM film

For high density magnetic recording, a perpendicular magnetized ultra fine grain medium having a large value of magnetic anisotropy is expected to be used, however non-uniformity in grain size becomes an origin of noise in reproduced signals. On the other hand, the continuous thin films such as rare earth transition metal (RE-TM) amorphous films used in magneto-optical recording have not such a noise source, however they do not show a sufficient wall coercivity for sustaining domains smaller than around 40 nm in mark length. One of the methods to solve these issues, we tried to fabricate RE-TM and Co thin films on the substrates which have self-assembled (SA) periodical nanometer-scale (nano) closed packed array of hollows (dents) at the surface. The array of dents have been produced from self organized 3-dimensional nano-pore (spherical cavity in nanometer scale) array in SiO₂ thin films. The SA nano-dent array is capable to use as an under layer which is providing periodically arranged nucleation sites for crystal growth. Here, we report the results of fabrication of the SA 3-dimensional nanopore films, the coercivity enhancement in perpendicular magnetized TbFeCo amorphous films, and Co dot-array films fabricated on the substrates which have the SA nano-dent array at the surface.