Lamellar phase separation and dynamic competition in La0.23Ca0.77MnO3.
We report the coexistence of lamellar charge-ordered (CO) and charge-disordered (CD) domains, and their dynamical behavior, in La0.23Ca0.77MnO3. Using high-resolution transmission electron microscopy (TEM), we show that below T(CD) approximately 170 K a CD-monoclinic phase forms within the established CO-orthorhombic matrix. The CD phase has a sheetlike morphology, perpendicular to the q vector of the CO superlattice (a axis of the Pnma structure). For temperatures between 64 and 130 K, both the TEM and resistivity experiments show a dynamic competition between the two phases: at constant T, the CD phase slowly advances over the CO one. This slow dynamics appears to be linked to the magnetic transitions occurring in this compound, suggesting important magnetoelastic effects.
Tao
J
J
Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Niebieskikwiat
D
D
Salamon
M B
MB
Zuo
J M
JM