Orbital order at Mn and O sites and absence of Zener polaron formation in manganites.
We report the doping dependence of the ground state of A-site ordered manganites below and above half doping. Energy and polarization dependence of the orbital reflection, taken by resonant soft-x-ray powder diffraction, at both Mn L(2,3) and O K edges, provides direct evidence for orbital order at Mn(3+) and oxygen sites and absence of Zener polaron formation. For x > or = 0.2 anomalous melting of the orbital order is observed, which is coupled neither to magnetic ordering nor to a structural transition, indicating a two-dimensional character of the interactions.
Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland.
M
M
García-Fernández
U
U
Staub
Y
Y
Bodenthin
V
V
Scagnoli
V
V
Pomjakushin
S W
SW
Lovesey
A
A
Mirone
J
J
Herrero-Martín
C
C
Piamonteze
E
E
Pomjakushina