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

我们用快速热退火（RTA）方法在Si衬底上热氧化SiO_2薄膜上成功地获得了由小晶粒FePt组成的垂直磁化薄膜。溅射法制备的FePt薄膜为连续薄膜，而快速热处理后薄膜变成（001）取向的L1_0相小晶粒，表现出垂直磁化。在室温到居里温度范围内，TbFeCo薄膜中过渡金属（TM）磁矩占主导地位。FePt的平均晶粒尺寸为直径29.6、16.6和7.0 nm，它们垂直磁化，具有高矫顽力（Hc），在Troom高达30-45 kOe。TbFeCo/FePt复合膜比单层TbFeCo膜具有更高的Hw、Hc和MsHw。我们还估算了TbFeCo和FePt之间的界面能，成功地制备了内部具有纳米凹坑的SiO_2薄膜，并表明溅射刻蚀可以有效地切掉表面的纳米凹坑阵列。通过自组装三嵌段共聚物胶束形成高度有序的纳米孔薄膜结构，采用磁光克尔效应（MOKE）和磁致光学二次谐波（MSHG）两种互补方法分别研究了薄膜本体和界面的磁化行为.观察到两种方法之间的明显差异，这可能仅与体中和膜界面处的不同磁行为有关。

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.