Direct imaging of nanoscale phase separation in La(0.55)Ca(0.45)MnO(3): relationship to colossal magnetoresistance.
A nanoscale phase is known to coincide with colossal magnetoresistance (CMR) in manganites, but its volume fraction is believed to be too small to affect CMR. Here we provide scanning-electron-nanodiffraction images of nanoclusters as they form and evolve with temperature in La(1-x)Ca(x)MnO(3), x = 0.45. They are not doping inhomogeneities, and their structure is that of the bulk compound at x = 0.60, which at low temperatures is insulating. Their volume fraction peaks at the CMR critical temperature and is estimated to be 22% at finite magnetic fields. In view of the known dependence of the nanoscale phase on magnetic fields, such a volume fraction can make a significant contribution to the CMR peak.
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. jtao@bnl.gov
J
J
Tao
D
D
Niebieskikwiat
M
M
Varela
W
W
Luo
M A
MA
Schofield
Y
Y
Zhu
M B
MB
Salamon
J M
JM
Zuo
S T
ST
Pantelides
S J
SJ
Pennycook