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Evidence of ultra-slow polaron dynamics in low-doped manganites from 139La NMR-NQR and muon spin rotation

G. Allodi·M. Cestelli Guidi·R. De Renzi·A. Caneiro·L. Pinsard
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Abstract

We report a 139La NMR investigation of low-doped insulating manganite samples (LaMnO(3+y) and La(1-x)Ca(x)MnO(3+y)) as a function of temperature. A volume fraction with fast nuclear relaxations was revealed by the inhomogeneous loss of the NMR signal over a broad temperature interval. Comparison with muSR data demonstrates that the wipe out of the 139La signal is mainly due to slowly fluctuating electric field gradients. This provides strong evidence for the slow diffusion of lattice excitations, identified with Jahn-Teller small polarons.

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G. Allodi, M. Cestelli Guidi, R. De Renzi, A. Caneiro, L. Pinsard. 2001-07-05. Evidence of ultra-slow polaron dynamics in low-doped manganites from 139La NMR-NQR and muon spin rotation. https://doi.org/10.1103/physrevlett.87.127206

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