Magnetic anisotropy in hole-doped superconducting Ba 0.67K 0.33Fe 2As2 probed by polarized inelastic neutron scattering
| Autor: | Zhang, Chenglin, liu, mengshu, Su, Yixi, Regnault, Louis-Pierre, Wang, Meng, Tan, Guotai, Bruckel, Th., Egami, Takeshi, Dai, Pengcheng |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | Physical Review B 87, 081101(R) (2013) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.87.081101 |
| Popis: | We use polarized inelastic neutron scattering (INS) to study spin excitations of optimally hole-doped superconductor Ba$_{0.67}$K$_{0.33}$Fe$_2$As$_{2}$ ($T_c=38$ K). In the normal state, the imaginary part of the dynamic susceptibility, $\chi^{\prime\prime}(Q,\omega)$, shows magnetic anisotropy for energies below $\sim$7 meV with c-axis polarized spin excitations larger than that of the in-plane component. Upon entering into the superconducting state, previous unpolarized INS experiments have shown that spin gaps at $\sim$5 and 0.75 meV open at wave vectors $Q=(0.5,0.5,0)$ and $(0.5,0.5,1)$, respectively, with a broad neutron spin resonance at $E_r=15$ meV. Our neutron polarization analysis reveals that the large difference in spin gaps is purely due to different spin gaps in the c-axis and in-plane polarized spin excitations, resulting resonance with different energy widths for the c-axis and in-plane spin excitations. The observation of spin anisotropy in both opitmally electron and hole-doped BaFe$_2$As$_2$ is due to their proximity to the AF ordered BaFe$_2$As$_2$ where spin anisotropy exists below $T_N$. Comment: 5 pages, 4 figures |
| Databáze: | arXiv |
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