Atomic ordering and coercivity mechanism in FePt and CoPt polycrystalline thin films

被引：44
作者：
Jeong, S [1 ]
Hsu, YN [1 ]
Laughlin, DE [1 ]
McHenry, ME [1 ]
机构：
[1] Carnegie Mellon Univ, Dept Mat Sci & Engn, Pittsburgh, PA 15213 USA
来源：
IEEE TRANSACTIONS ON MAGNETICS | 2001年 / 37卷 / 04期
基金：
美国国家科学基金会; 美国安德鲁·梅隆基金会;
关键词：
atomic ordering; coercivity mechanism; CoPt and FePt; thin films;
D O I：
10.1109/20.950823
中图分类号：
TM [电工技术]; TN [电子技术、通信技术];
学科分类号：
0808 ; 0809 ;
摘要：
40 nm thick CoPt and FePt films were prepared on oxidized Si substrates with 10 nm MgO underlayers. The maximum coercivity (H-c) for CoPt films was found to be similar to 10 kOe after annealing at 700 degreesC for similar to 20-30 minutes (min). Structural analysis showed a significant amount of FCC phase as well as the ordered L1(0) phase in these films. FePt films showed an abrupt increase of ordered volume fraction and H-c in the initial stage of annealing and predominance of the tetragonal L1(0) phase after 10 min. at 700 degreesC. The maximum H-c reached similar to 16 kOe after annealing at 700 degreesC for more than 20 minutes. Dark field (DF) images of the annealed CoPt films showed individual grains which exhibited a possibility of several variants or disordered phase with dimensions similar to the exchange correlation length, b(cm). The temperature dependence of H-c seems to indicate a weak pinning mechanism in the highly ordered FePt films. Magnetic force microscopy indicated a complex domain structure consisting of clusters with dimensions of several hundred nanometers.
引用
收藏
页码：1299 / 1301
页数：3
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