Phys. Rev. Lett. 80, 1316–1319 (1998)Softening and Broadening of the Zone Boundary Magnons in Pr0.63Sr0.37MnO3Received 14 March 1997; revised 3 October 1997; published in the issue dated 9 February 1998 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 boundary magnons 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. © 1998 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.80.1316
DOI:
10.1103/PhysRevLett.80.1316
PACS:
75.30.Ds
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