Magneto-elastically coupled structural, magnetic and superconducting   order parameters in BaFe$_{2}$(As$_{1-x}$P$_{x}$)$_{2}$
  We measure the transport properties of mechanically strained single crystals of BaFe$_{2}$(As$_{1-x}$P$_{x}$)$_{2}$ over a wide range of $x$. The N\'eel transition is extremely sensitive to stress and this sensitivity increases as optimal doping is approached, even though the transition itself is strongly suppressed. Furthermore, we observe significant changes in the superconducting transition temperature with applied strain, which mirror changes as a function of the composition $x$. These experiments are a direct illustration of the intimate coupling between different degrees of freedom in iron-based superconductors, revealing the importance of magneto-elastic coupling to the magnetic and superconducting transition temperatures. 
H-.H. Kuo and James G. Analytis and J.-H. Chu and R. M. Fernandes and   J. Schmalian and I. R. Fisher
cond-mat.supr-con