Composite magnetic films for ultrahigh density opt-magnetic hybrid recording (Approach from magneto optical recording film)

点击翻译按钮获取中文摘要

We have succeeded to obtain perpendicular magnetized films consists of small grains of FePt by using a rapid thermal annealing : RTA method on to thermally oxidized SiO_2 thin films on Si substrates. As deposited films of FePt by sputtering method are continuous films, however after RTA they become small grains of (001) oriented L1_0 phase crystalline structure showing a perpendicular magnetization. The average grain diameter is strongly depended on the film thickness of as sputtered film before RTA.TbFeCo film is fabricated on isolated FePt grains to increase the domain wall coercivity (Hw) of TbFcCo film by exchange coupling effect between TbFeCo and FePt The transition metal(TM) moment has a dominant charge in TbFeCo film langing from room temperature (Troom) to Curie temperature. The FePt has average grain sizes such as 29.6, 16.6 and 7.0 nm in diameter, which are perpendicularly magnetized with a high coercivity (Hc), as high as 30-45 kOe at Troom. The TbFeCo/FePt composite film shows higher Hw, Hc and MsHw than those of the singe ayer of TbFeCo film. We also estimate the amount of interfacial wal energy between TbFeCo and FePt.We succeeded to fabricate SiO_2 film having nano-hollowws inside and show that the spatter etching is effective to crop out the nano-dent array at the surface. The highly ordered structure of the nano-pore thin film is formed by ordering of self-assembled triblock copolymer micelles.Two complementary methods, namely the magneto-optical Kerr effect (MOKE) and magnetically induced optical second harmonic generation (MSHG) were used to detect the magnetization behavior in the bulk of the film and at its interfaces, respectively. A clear difference between the two methods was observed that could only be related to the different magnetic behavior in the bulk and at the interfaces of the film.