Observation of two time scales in the ferromagnetic manganite La1-xCaxMnO3, x approximately 0.3.
We report new zero-field muon spin relaxation and neutron spin echo measurements in ferromagnetic (FM) (La,Ca)MnO3 which suggest at least two spatially separated regions possessing very different Mn-ion spin dynamics. One region displays diffusive relaxation, "critical slowing down" near T(C) and an increasing volume fraction below T(C), suggesting overdamped FM spin waves below T(C). The second region possesses more slowly fluctuating spins, a linewidth independent of q, and a decreasing volume fraction below T(C). The estimated length scale for the inhomogeneity is <or=30 A.
Heffner
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RH
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Sonier
J E
JE
MacLaughlin
D E
DE
Nieuwenhuys
G J
GJ
Ehlers
G
G
Mezei
F
F
Cheong
S W
SW
Gardner
J S
JS
Röder
H
H