Abstract: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 La1-xCaxMnO3, 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.
Note:(highlighted in Physics Today, Nov. issue, p20-23; highlighted in Parity (in Japanese))
First Author:Tao, J.; Niebieskikwiat D.; Varela M.; Luo W.; Schofield M. A; Zhu Y.; Salamon M. B.; Zuo J. M.; Pantelides S. T.; Pennycook S. J.
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