Glassy Behavior in Iron Superconductors

The iron pnictide superconductors continue to reveal complex and rich new physics.  In a recent study, we have uncovered glassy dynamics in the prototypical iron pnictide superconductor, Ba(Fe,Co)2As2.  Whereas static measurements of this

material indicate a highly homogeneous material, our microscopic dynamical measurements reveal that the relaxation dynamics is inhomogeneous.  The reason for this behavior is likely due to the strong coupling between the antiferromagnetic and nematic order parameters.  Small strain fields due to the Co dopants or crystalline defects can cause glassy nematic fluctuations, which are then mirrored in the magnetic dynamics that we observe. This work, led by postdoc Adam Dioguardi, was recently published as an Editor’s Suggestion in Physical Review B.  This work was a collaboration with Iowa State University, and the National High Magnetic Field Laboratory in Tallahassee, Florida.