Intermittent dynamics of antiferromagnetic phase in inhomogeneous iron-based chalcogenide superconductor

Layered superconductors are electronically inhomogeneous systems, characterized by the interplay of charge, lattice, and magnetic degrees of freedom. Intrinsic phase separation and texturing at different length scales are natural consequences of this interplay. Here, the authors have studied atomic motion in nanodomains of an inhomogeneous iron-based superconductor with coexisting metallic and antiferromagnetic phases, exploiting evolution of speckles produced by coherent x-ray scattering. They show that the majority antiferromagnetic phase has an avalanchelike dynamics, which changes anomalously across the superconducting transition temperature. The results suggest relevance of glassy dynamics in the quantum phenomena occurring in inhomogeneous matter.