Ultraslow polaron dynamics in low-doped manganites from La-139 NMR-NQR andmuon spin rotation - art. no. 127206

We report a La-139 NMR investigation of low-doped insulating manganite samp les (LaMnO3+delta and La1-yCayMnO3+delta) as a function of temperature. A v olume fraction with fast nuclear relaxations was revealed by the inhomogene ous loss of the NMR signal over a broad temperature interval. Comparison wi th muon spin rotation data demonstrates that the wipeout of the La-139 sign al is mainly due to slowly fluctuating electric field gradients. This provi des strong evidence for the slow diffusion,of lattice excitations, identifi ed with Jahn-Teller small polarons.