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Unformatted text preview: tern was observed for films grown at 500 C, as shown in Figure 1(d) , indicating that the films were epitaxially grown with an island 3D growth mode and has the rough surface. Figure 2 shows AFM images of 1000 A ˚ Fe-Ga films grown at different temperatures. The average roughnesses of the thin films are determined to be 5.2, 7.6, and 9.2 nm for growth temperature of 300, 400, and 500 C, respectively. With increasing growth temperature, the surface morphology is gradually roughened. Figs. 2(d) – 2(f) show the surface of the films with different growth temperatures. The homogene- ous films were obtained for all samples. The XRD patterns of the thin films grown at different temperatures are shown in Fig. 3 . The (001) and (002) dif- fraction peaks corresponding to bcc a-Fe crystal structure (A2) are observed for all films, indicating that single bcc a-Fe phase Fe-Ga alloys with (001) crystal orientation were grown on the GaAs(100) substrate. The results are consistent with our previous report. 25 However, the peak of Fe 3 Ga(004) was observed for films grown at 400 C. The intensity of this peak became stronger and sharper with further increase in the grown temperature, as seen in the inset of Figure 2 . Note that the Fe 3 Ga has a DO 3 structure and it can be epitaxially grown on the GaAs(001) substrate. 26 , 27 Figures 4(a) and 4(b) show the magnetic hysteresis (M-H) loops of Fe-Ga and Fe 3 Ga/Fe-Ga films in both out-of-plane and in-plane magnetic field directions at room temperature. It can be seen that while the Fe-Ga film exhibits the in-plane mag- netic anisotropy, the out-of-plane magnetic anisotropy of the Fe 3 Ga/Fe-Ga film is stronger than that of the Fe-Ga film. van’t Erve et al. reported that the Fe 3 Ga thin film with DO 3 structure exhibited an out-of-plane magnetic anisotropy, which is FIG. 1. The RHEED patterns of (a) GaAs(001) substrate, and (b)–(d) Fe-Ga thin film grown at 300, 400, and 500 C, respectively. FIG. 2. (a)–(c) AFM and (d)–(f) FE-SEM images of the samples grown at 300, 400, and 500 C, respectively. FIG. 3. The h-2 h XRD patterns of thin films grown at selected growth tem- perature. Inset shows the high angle scanner from 60 to 70 . 17C734-2 D. D. Dung and S. Cho J. Appl. Phys. 113 , 17C734 (2013) Downloaded 27 May 2013 to 22.214.171.124. This article is copyrighted as indicated in the abstract. Reuse of AIP content is subject to the terms at: http://jap.aip.org/about/rights_and_permissions consistent with the result calculated for the same DO 3 structure by Wu et al. , 26 , 28 Figures 4(c) and 4(d) show diagrams of possi- ble spin configurations for Fe-Ga and Fe 3 Ga/Fe-Ga films, respectively, where magnetic moments rotate with applied mag- netic field in both in-plane and perpendicular directions. Since Fe 3 Ga clusters with perpendicular magnetic anisotropy were embedded in Fe-Ga, the out-of-plane magnetic anisotropy of the Fe 3 Ga/Fe-Ga film was stronger than that of the Fe-Ga film....
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- Fall '13
- Magnetism, Magnetic Field, Magnetic moment, Magnetic anisotropy, out-of-plane magnetic anisotropy, in-plane magnetic anisotropy