Magnetic fluctuation and frustration in new iron-based layered SrFe1-xCoxAsF superconductors

作者：Wang W^*; Li B; Liu S; Liu M; Xing Z W

来源：Journal of Applied Physics, 2010, 107(12): 123906.

DOI：10.1063/1.3448233

By using the first-principle calculations, we study structural, electronic, and magnetic properties of the SrFeAsF compound and its Co-doped counterpart SrFe1-xCoxAsF (x=0.125). It is shown that for SrFeAsF, the competition between exchange couplings J(1) and J(2) of the nearest and next-nearest neighboring Fe ions gives rise to a striped antiferromagnetic (AFM) order, accompanied by structural distortions. At the Co doping of x=0.125, we obtain J(1)/2J(2)similar to 1, suggesting that the AFM order encounter frustration and the system be in a critical state between the spin density wave state and disordered spin glass state with strong magnetic fluctuations. By comparing the doped compound with the undoped one, it is found that the itinerancy of Fe 3d electrons increases and the density of states at the Fermi level increases significantly, favorable for superconductivity due to magnetic fluctuations.

• 出版日期2010-6-15
• 单位南京大学; 东南大学