Glass transition in the polaron dynamics of colossal magnetoresistive manganites.
Neutron scattering measurements on a bilayer manganite near optimal doping show that the short-range polaron correlations are completely dynamic at high T, but then freeze upon cooling to a temperature T(*) approximately equal 310 K. This glass transition suggests that the paramagnetic/insulating state arises from an inherent orbital frustration that inhibits the formation of a long-range orbital- and charge-ordered state. Upon further cooling into the ferromagnetic-metallic state (T(C) = 114 K), where the polarons melt, the diffuse scattering quickly develops into a propagating, transverse optic phonon.
Argyriou
D N
DN
Materials Science Division, Argonne National Laboratory, Argonne, Illinois, 60439, USA.
Lynn
J W
JW
Osborn
R
R
Campbell
B
B
Mitchell
J F
JF
Ruett
U
U
Bordallo
H N
HN
Wildes
A
A
Ling
C D
CD