Phase-segregated Glass Formation Linked to Long-Range Strain using Resonant Ultrasound Spectroscopy

We have observed a very large damping of ultrasonic waves in the magnetically/electronically/structurally phase segregated state of a CMR manganite that suddenly disappears upon the formation of a glassy state. A subtle stiffening of the shear modulus accompanies the putative glass transition. Our observations most explicitly link strain to the proposed formation of an unusual glass state composed of coexisting, macroscopic structural domains found in this material. These results may implicate strain as the determining factor in the formation of non-equilibrium mixed-phase states in other systems that display widely hysteretic first order magneto-structural transitions.