Magnetotransport studies of optimally doped Sr(Fe${_{1-x}}$Co${_x}$)${_2}$As${_2}$

Abstract

We report magnetotransport measurements and its scaling analysis for the optimally electron doped Sr(Fe${_{0.88}}$Co${_{0.12}}$)${_2}$As${_2}$ system. We pbserve that both the Kohler's and modified Kohler's scalings are violated. Interestingly, the Hall angle displays a quadratic temperature dependence similar to many cuprates and heavy fermion systems. The fact that this temperature dependence is seen in spite of the violation of modified Kohler's scaling suggests that the Hall angle and the magnetoresistance are not governed by the same scattering mechanism. We also observe a linear magnetoresistance in this system, which does not harbor a spin density wave ground state. Implcations of our observations are discussed in the context of spin fluctuations in strongly correlated electron systems.