Evolution of granular to particulate structure of (001) FePt on amorphous substrates (invited)
Evolution of granular to particulate structure of (001) FePt on amorphous substrates (invited)
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DOI：
10.1063/1.2835442
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发表时间：
2008-02
影响因子：
3.2
通讯作者：
Yun-chung Wu;Liang-Wei Wang;M. Rahman;C. Lai
中科院分区：
文献类型：
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作者：
Yun-chung Wu;Liang-Wei Wang;M. Rahman;C. Lai
通过沉积原子尺度的Fe scinPt scinSiO 2多层膜，然后通过各种退火条件，在非晶SiO2或玻璃衬底上获得了良好取向的（001）取向的颗粒或颗粒L10 FePt膜。经350°C退火后，得到了平均晶粒尺寸为5.14nm、垂直取向度为7.7kOe、矩形度为0.95的（001）FePt-SiO2颗粒膜。SiO2向FePt晶界和自由表面的扩散加速了Fe和Pt原子的扩散，形成L10相，从而实现了FePt的低温有序化。通过将退火温度进一步升高至700°C，获得了取向的（001）单晶的分离颗粒。由于低表面能SiO2的存在，在低温下发生空隙的成核，然后进行团聚过程，导致颗粒结构。分离出的颗粒显示出60 kOe的垂直方向的垂直度和单位的方形度。
Well-aligned (001)-oriented granular or particulate L10 FePt films on amorphous SiO2 or glass substrates were obtained by depositing atomic-scale Fe∕Pt∕SiO2 multilayers followed by various postannealing conditions. After 350°C annealing, (001) FePt–SiO2 granular films were obtained with an average grain size of 5.14nm, perpendicular coercivity of 7.7kOe, and squareness of 0.95. The diffusion of SiO2 to grain boundaries and free surface of FePt accelerated the diffusion of Fe and Pt atoms to form the L10 phase; therefore, low-temperature ordering of FePt was achieved. By further raising the annealing temperature to 700°C, isolated particles of aligned (001) single crystals were achieved. The nucleation of voids occurred at low temperatures due to the existence of low-surface-energy SiO2, and then an agglomeration process proceeded, leading to a particulate structure. The isolated particles showed a perpendicular coercivity of 60kOe and squareness of unity.