Direct evidence for the effect of lattice distortions in the transport properties of perovskite-type manganite films

We report ion channeling investigations in crystalline colossal magnetoresistance films of (Formula presented)(Formula presented)(Formula presented), (Formula presented)(Formula presented)(Formula presented), and (Formula presented)(Formula presented)(Formula presented). The measured full width at half maximum of the channeling angular scans exhibit a dramatic increase with decreasing temperature which is larger than expected from a simple Debye model. The temperature range where such a change is observed overlaps with the peak magnetoresistance regions in the three cases. The observed effect is an order of magnitude larger than previously found by volumetric measurements and seems to provide a direct evidence for a dynamic Jahn-Teller distortion. © 1996 The American Physical Society.