Anomalously large change in sound velocity in erbium orthoferrite
Buchel'nikov V. D., Bychkov I. V., Shavrov V. G.
An explanation is offered for the substantial (25%) decrease in the velocity of a quasielastic wave and for the behavior of the soft quasispin-vibration mode in ErFe03 near the Γ2-Γ12 orientational phase transition.