Magnetic properties of Ca-doped SrRuO3 from full-potential calculations
Magnetic properties of Ca-doped SrRuO3 from full-potential calculations
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DOI：
10.1016/s0022-4596(03)00386-4
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发表时间：
2004
影响因子：
3.3
通讯作者：
R. Vidya;P. Ravindran;A. Kjekshus;H. Fjellvåg;B. Hauback
中科院分区：
文献类型：
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作者：
R. Vidya;P. Ravindran;A. Kjekshus;H. Fjellvåg;B. Hauback
我们对Sr1 − xCaxRuO3（x = 0、0.25、0.5、0.75和1）在对位、铁磁、A型、C型和G型反铁磁结构中进行了精确的广义梯度校正的完全相对论全势计算。我们已经进行了电子结构计算实验观察到的正交结构以及假设的立方结构。我们的研究结果进行了分析的帮助下，总，网站，自旋和轨道投影的态密度。总能量研究表明CaRuO3稳定在G型反铁磁态。由于Ca~（2+）的半径较小，使Ru~（4d）和O~（2p）之间的杂化作用减弱，从而导致八面体的倾斜。这种弱杂交沿着交换分裂导致接近费米能级的赝隙状特征，这应该稳定CaRuO3中的G型反铁磁有序。然而，粉末中子衍射数据CaRuO3采取在8和298 K没有显示任何磁峰，这意味着CaRuO3表现出自旋玻璃状的状态，占主导地位的短程反铁磁相互作用。计算的Sr1 − xCaxRuO3的磁基态与实验结果一致。我们还计算了G型CaRuO_3的光学光谱、X射线和紫外光电子能谱以及Ru和O的K边X射线吸收谱，并与实验结果吻合较好。
We have carried out accurate generalized-gradient-corrected fully-relativistic full-potential calculations for Sr1−xCaxRuO3(x=0, 0.25, 0.5, 0.75, and 1) in para-, ferro-, and A-, C-, and G-type antiferromagnetic configurations. We have performed electronic structure calculations for the experimentally observed orthorhombic structure as well as the hypothetical cubic structure. Our results are analyzed with the help of total, site-, spin-, and orbital-projected density of states. The total-energy studies show that CaRuO3stabilizes in the G-type antiferromagnetic state. The octahedral tilting owing to the relatively small radius of Ca2+leads to weak hybridization between Ru 4d and O 2p. This weak hybridization along with exchange splitting causes a pseudogap-like feature close to the Fermi level, which should stabilize G-type antiferromagnetic ordering in CaRuO3. However, powder neutron diffraction data on CaRuO3taken at 8 and 298 K do not show any magnetic peaks, implying that CaRuO3exhibits a spin-glass-like state with dominant short-range antiferromagnetic interaction. The calculated magnetic ground state of Sr1−xCaxRuO3is found to be consistent with the experimental findings. We have also calculated optical spectra as well as X-ray and ultra-violet photoemission spectra and Ru and O K-edge X-ray absorption spectra for G-type CaRuO3and found good agreement with available experimental spectra.