Enhanced uniaxial magnetic anisotropy in Fe31Co69 thin films on GaAs(001)
Enhanced uniaxial magnetic anisotropy in Fe31Co69 thin films on GaAs(001)
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DOI：
10.1063/1.2998973
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发表时间：
2008-10
影响因子：
3.2
通讯作者：
F. Bianco;P. Bouchon;M. Sousa;G. Salis;S. Alvarado
中科院分区：
文献类型：
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作者：
F. Bianco;P. Bouchon;M. Sousa;G. Salis;S. Alvarado
本文报道了在GaAs(001)衬底上生长的厚度为1-9 nm的Fe31Co69薄膜的生长后退火对其磁各向异性的影响。利用磁光克尔效应得到的磁滞回线显示出平面内的单轴磁各向异性，易轴通常沿[110]衬底方向。有效面内各向异性常数和垂直各向异性常数K_(⊥)均随退火温度呈拟线性的陡峭增加。在300℃下对1.9 nm厚的薄膜进行10分钟的退火处理，可使薄膜的库夫数从生长时的8.9×103增加到1.1×105J/m~3。库夫斜率随退火温度的增加与薄膜厚度近似成反比。这些观察结果可以用发生在铁磁-半导体界面上的热致结构改变来解释。X射线掠入射薄膜应变测量结果表明，生长后的K-⊥和K-K薄膜的退火演化对薄膜的生长有一定的影响。
We report on the effect of postgrowth annealing on the magnetic anisotropy of Fe31Co69 thin epitaxial films, 1–9 nm thick, and grown on GaAs(001) substrates. Hysteresis curves obtained by means of the magneto-optical Kerr effect reveal an in-plane uniaxial magnetic anisotropy with the easy axis typically along the [110] substrate direction. The effective in-plane and perpendicular anisotropy constants, Kueff and K⊥eff, exhibit a steep quasilinear increase with the annealing temperature. Annealing a 1.9-nm-thick film for 10 min at 300 °C results in an increase in Kueff from the as-grown value of 8.9×103 to 1.1×105 J/m3. The slope of Kueff versus annealing temperature increases approximately as the inverse of the film thickness. These observations can be accounted for by a thermally induced structural modification occurring in the ferromagnet-semiconductor interface. Film-strain measurements performed by x-ray grazing-incidence diffraction indicate that the postgrowth annealing evolution of Kueff and K⊥eff ...