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E. W. Plummer

Publications and source records attributed to E. W. Plummer.

38 records · Page 3Linked to original sources
arXiv2001

Microscopic spin interactions in the CMR manganites

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.

cond-mat.str-el↗
arXiv2000

Short-range polaron correlations in the ferromagnetic La(1-x)Ca(x)MnO(3)

We use neutron scattering to demonstrate the presence of lattice polarons and their short-range correlations for several samples of La$_{1-x}$Ca$_x$MnO$_3$ in the Ca doping range $0.15\leq x\leq 0.3$. We establish the doping dependence of the orientation, commensuration, and coherence length of the polaron correlations and show that the populations of correlated and uncorrelated polarons are intimately related to the transport properties of the materials.

cond-mat.str-el↗