Weak charge-lattice coupling requires reinterpretation of stripes of charge order in La1-xCaxMnO3.
Modulations in manganites attributed to stripes of charge/orbital/spin order are thought to result from strong electron-lattice interactions that lock the superlattice and parent lattice periodicities. Surprisingly in La1-xCaxMnO3 (x>0.5,90 K), convergent beam (3.6 nm spot) electron diffraction patterns rule out charge stacking faults and indicate a superlattice with uniform periodicity. Moreover, large area electron diffraction peaks are sharper than simulations with stacking faults. Since the electron-lattice coupling does not lock the two periodicities (to yield stripes) it may be too weak to strongly localize charge.
Loudon
J C
JC
Department of Materials Science, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom.
Cox
S
S
Williams
A J
AJ
Attfield
J P
JP
Littlewood
P B
PB
Midgley
P A
PA
Mathur
N D
ND