Softening and Broadening of the Zone Boundary Magnons in Pr0.63Sr0.37MnO3
نویسندگان
چکیده
We have studied the spin dynamics in Pr0.63Sr0.37MnO3 above and below the Curie temperature TC = 301 K. Three distinct new features have been observed: a softening of the magnon dispersion at the zone boundary for T < TC , significant broadening of the zone boundarymagnons as T → TC , and no evidence for residual spin-wave like excitations just above TC . The results are inconsistent with double exchange models that have been successfully applied to higher TC samples, indicating an evolution of the spin system with decreasing TC . Typeset using REVTEX
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