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Evolution of spin-wave excitations in ferromagnetic metallic manganites

F. Ye·Pengcheng Dai·J. A. Fernandez-Baca·Hao Sha·J. W. Lynn·H. Kawano-Furukawa·Y. Tomioka·Y. Tokura·Jiandi Zhang
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Abstract

Neutron scattering results are presented for spin-wave excitations of three ferromagnetic metallic $A_{1-x}A^{\prime}_{x}$MnO$_3$ manganites (where $A$ and $A^\prime$ are rare- and alkaline-earth ions), which when combined with previous work elucidate systematics of the interactions as a function of carrier concentration $x$, on-site disorder, and strength of the lattice distortion. The long wavelength spin dynamics show only a very weak dependence across the series. The ratio of fourth to first neighbor exchange ($J_4/J_1$) that controls the zone boundary magnon softening changes systematically with $x$, but does not depend on the other parameters. None of the prevailing models can account for these behaviors.

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F. Ye, Pengcheng Dai, J. A. Fernandez-Baca, Hao Sha, J. W. Lynn, H. Kawano-Furukawa, Y. Tomioka, Y. Tokura, Jiandi Zhang. 2005-12-16. Evolution of spin-wave excitations in ferromagnetic metallic manganites. https://doi.org/10.1103/physrevlett.96.047204

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