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Microscopic spin interactions in the CMR manganites

J. A. Fernandez-Baca·Pengcheng Dai·H. Kawano-Furukawa·H. Yoshizawa·E. W. Plummer·S. Katano·Y. Tomioka·Y. Tokura
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Abstract

Using inelastic neutron scattering we measured the microscopic magnetic coupling associated with the ferromagnetic (FM) clusters of the ``colossal magnetoresistance'' (CMR) compound Pr$_{0.70}$Ca$_{0.30}$MnO$_3$. When the insulating to metal (I-M) transition is induced by an external magnetic field there is a discontinuous change in the spin-wave stiffness constant. This result indicates that the probed regions undergo a first-order transition from an insulating to a metallic state, and that there are no FM metallic domains in the insulating region. We argue that the I-M transition in the CMR manganites is more complex than the simple percolation of large FM metallic clusters.

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J. A. Fernandez-Baca, Pengcheng Dai, H. Kawano-Furukawa, H. Yoshizawa, E. W. Plummer, S. Katano, Y. Tomioka, Y. Tokura. 2001-10-31. Microscopic spin interactions in the CMR manganites. https://arxiv.org/abs/cond-mat/0110659

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