Evolution of magnetic anisotropy in epitaxial Fe films by ferromagnetic resonance
Evolution of magnetic anisotropy in epitaxial Fe films by ferromagnetic resonance
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DOI：
10.1063/1.1543912
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发表时间：
2003-05
影响因子：
3.2
通讯作者：
Y. Zhai;L. Shi;Wen Zhang;Yunxia Xu;Ming-Hui Lu;H. Zhai;W. Tang;X. Jin;Yongbing Xu;J. Bland
中科院分区：
文献类型：
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作者：
Y. Zhai;L. Shi;Wen Zhang;Yunxia Xu;Ming-Hui Lu;H. Zhai;W. Tang;X. Jin;Yongbing Xu;J. Bland
用铁磁共振（FMR）方法研究了用分子束外延法在GaAs（100）衬底上生长的4 ~ 33层单晶Fe膜。观察到了面内和面外各向异性的演化。FMR数据显示，厚度t小于12.7 ML的薄膜具有明显的面内单轴磁各向异性，易磁化轴沿着<11_0>方向。当t=8.4 ML时，由于立方磁晶各向异性引起的面内四重各向异性开始出现并与单轴磁各向异性共存，并随膜厚的增加而增加。当t=33 ML时，立方各向异性常数K1达到28.2×104 erg/cm ~ 3，是体心立方Fe的60%。观察到了强的垂直各向异性的Fe 3 O 4薄膜。当t=4 ML时，垂直各向异性常数高达14.6×106 erg/cm ~ 3。随着厚度t的增加，它减小，33 ML时达到2.1×106 erg/cm 3，同时出现小的四阶垂直各向异性，并使厚度t增加。
Single-crystal Fe films of 4 to 33 monolayers (ML) on GaAs (100) prepared by molecular-beam epitaxy were studied by ferromagnetic resonance (FMR). The evolution of both in-plane and out-of-plane anisotropies was observed. The FMR data show a predominant in-plane uniaxial magnetic anisotropy in the films with the thickness t less than 12.7 ML, with an easy axis along the 〈11_0〉 direction. An in-plane fourfold anisotropy due to cubic magnetocrystalline anisotropy starts to appear and coexists with uniaxial magnetic anisotropy when t=8.4 ML, and increases with increasing film thickness. For t=33 ML, the cubic anisotropy constant K1 reaches 28.2×104 erg/cm3, which is 60% of the value for bulk bcc Fe. A strong perpendicular anisotropy in the ultrathin Fe films was observed. For t=4 ML, the perpendicular anisotropy constant is as high as 14.6×106 erg/cm3. It decreases with increasing the thickness t and reaches about 2.1×106 erg/cm3 for 33 ML, while a small fourth-order perpendicular anisotropy appears and incr...