Kumar Manish, Nautiyal Tashi, Auluck Sushil
Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, India. Department of Physics, Kurukshetra University, Kurukshetra 136119, India.
J Phys Condens Matter. 2009 May 13;21(19):196003. doi: 10.1088/0953-8984/21/19/196003. Epub 2009 Apr 16.
We have calculated the magneto-optical (MO) properties of Co(2)FeX (X = Al, Ga, Si and Ge) Heusler compounds using the full potential linearized augmented plane wave (FPLAPW) method as implemented in the WIEN2K code using the local spin density approximation (LSDA) and also by using the generalized gradient approximation (GGA) for the electronic exchange and correlation. In all the compounds, Kerr rotation θ(K) has a strong minimum near 2 eV, the value of |θ(K)| corresponding to this minimum being almost as large as in pure Co-Fe compounds. The calculated MO spectra help to identify the features of the experimental spectra. A comparison of the results shows that the Kerr spectrum is quite similar from both LSDA and GGA but the latter gives better agreement with experiment. Moreover, we find that inclusion of correlation effects using GGA+U removes the discrepancy in magnetic moment of Co(2)FeX (X = Si, Ge) though it has an insignificant effect on the Kerr spectra.
我们使用WIEN2K代码中实现的全势线性缀加平面波（FPLAPW）方法，采用局域自旋密度近似（LSDA），并通过对电子交换和关联使用广义梯度近似（GGA），计算了Co₂FeX（X = Al、Ga、Si和Ge）赫斯勒化合物的磁光（MO）性质。在所有化合物中，克尔旋转角θ(K)在2电子伏特附近有一个很强的极小值，对应于这个极小值的|θ(K)|值几乎与纯Co-Fe化合物中的一样大。计算得到的MO光谱有助于识别实验光谱的特征。结果比较表明，LSDA和GGA得到的克尔光谱非常相似，但后者与实验结果的吻合度更好。此外，我们发现使用GGA+U包含关联效应消除了Co₂FeX（X = Si、Ge）磁矩的差异，尽管它对克尔光谱的影响微不足道。
