First-order metal-insulator transitions in manganites: are they universal?
Conductivity data for La(2-2x)Sr(1+2xMn2O7 (x = 0.6) show a first-order transition from an orbital- or charge-ordered insulator to a metal as the temperature falls below approximately 160 K. The change in conductivity is 100 times larger than that seen previously in any single-phase manganite in zero field. The metallic low-temperature state is similar to x = 0.58, but x = 0.58 shows no evidence of orbital or charge order. This result supports a conclusion that strongly coupled magnetic-conductive transitions are first order.
Li
Qing' An
QA
Chinese Academy of Sciences, Beijing, China.
Gray
K E
KE
Ancona
S Nyborg
SN
Zheng
H
H
Rosenkranz
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S
Osborn
R
R
Mitchell
J F
JF