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Softening and Broadening of the Zone Boundary Magnons in Pr0.63Sr0.37MnO3

H. Y. Hwang·P. Dai·S-W. Cheong·G. Aeppli·D. A. Tennant·H. A. Mook
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Abstract

We have studied the spin dynamics in Pr$_{0.63}$Sr$_{0.37}$MnO$_3$ above and below the Curie temperature $T_C=301$ K. Three distinct new features have been observed: a softening of the magnon dispersion at the zone boundary for $T<T_C$, significant broadening of the zone boundary magnons as $T\to T_C$, and no evidence for residual spin-wave like excitations just above $T_C$. The results are inconsistent with double exchange models that have been successfully applied to higher $T_C$ samples, indicating an evolution of the spin system with decreasing $T_C$.

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H. Y. Hwang, P. Dai, S-W. Cheong, G. Aeppli, D. A. Tennant, H. A. Mook. 1997-10-15. Softening and Broadening of the Zone Boundary Magnons in Pr0.63Sr0.37MnO3. https://doi.org/10.1103/physrevlett.80.1316

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