"Scaling of the Stress and Temperature Dependence of the Optical Anisotropy in Ba(Fe1−xCox)2As2"

C. Mirri: A. Dusza, S. Bastelberger, J.-H. Chu, H.-H. Kuo, I. R. Fisher, L. Degiorgi; Journal of Superconductivity and Novel Magnetism, 09/15/16.

Additional Authors: A. Dusza, S. Bastelberger, J.-H. Chu, H.-H. Kuo, I. R. Fisher, L. Degiorgi


We revisit our recent investigations of the optical properties in the underdoped regime of the title compounds with respect to their anisotropic behavior as a function of both temperature and uniaxial stress across the ferro-elastic tetragonal-to-orthorhombic transition. By exploiting a dedicated pressure device, we can tune and control uniaxial stress in situ thus changing the degree of detwinning of the samples in the orthorhombic SDW state as well as pressure-inducing an orthorhombicity in the paramagnetic tetragonal phase. We discover a hysteretic behavior of the optical anisotropy; its stress versus temperature dependence across the structural transition bears testimony to the analogy with the magnetic-field versus temperature dependence of the magnetization in a ferromagnet when crossing the Curie temperature. In this context, we find furthermore an intriguing scaling of the stress and temperature dependence of the optical anisotropy in Ba(Fe1−xCox)2As2.