Magnetoelastic coupling and charge correlation lengths in a twin domain of Ba(Fe1-xCox)(2)As-2 (x=0.047): A high-resolution x-ray diffraction study

作者：Zhang Qiang^*; Wang Wenjie; Kim Jong Woo; Hansen Benjamin; Ni Ni; Bud' ko Sergey L; Canfield Paul C; McQueeney Robert J; Vaknin David

来源：Physical Review B, 2013, 87(9): 094510.

DOI：10.1103/PhysRevB.87.094510

The interplay between structure, magnetism, and superconductivity in single crystal Ba(Fe1-xCox)(2)As-2 (x = 0.047) has been studied using high-resolution x-ray diffraction by monitoring charge Bragg reflections in each twin domain separately. The emergence of the superconducting state is correlated with the suppression of the orthorhombic distortion around T-C, exhibiting competition between orthorhombicity and superconductivity. Above T-S, the in-plane charge correlation length increases with the decrease of temperature, possibly induced by nematic fluctuations in the paramagnetic tetragonal phase. Upon cooling, anomalies in the in-plane charge correlation lengths along a (xi(a)) and b axes (xi(b)) are observed at T-S and also at T-N indicative of strong magnetoelastic coupling. The in-plane charge correlation lengths are found to exhibit anisotropic behavior along and perpendicular to the in-plane component of stripe-type AFM wave vector (101)(O) below around T-N. The temperature dependence of the out-of-plane charge correlation length shows a single anomaly at T-N, reflecting the connection between Fe-As distance and Fe local moment. The origin of the anisotropic in-plane charge correlation lengths xi(a) and xi(b) is discussed on the basis of the antiphase magnetic domains and their dynamic fluctuations. DOI: 10.1103/PhysRevB.87.094510

• 出版日期2013-3-18