Ultraslow 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

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Lugar: New York; Año: 2001 vol. 87 p. 127206 - 127210

0031-9007

We report a 139La NMR investigation of low-doped insulating manganite samples (LaMnO31d andLa12yCayMnO31d) as a function of temperature. A volume fraction with fast nuclear relaxations wasrevealed by the inhomogeneous loss of the NMR signal over a broad temperature interval. Comparisonwith muon spin rotation data demonstrates that the wipeout of the 139La signal is mainly due to slowlyfluctuating electric field gradients. This provides strong evidence for the slow diffusion of lattice excitations,identified with Jahn-Teller small polarons.