Lamellar phase separation and dynamic competition in La0.23Ca0.77MnO3

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Chemistry

Background:

• La0.23Ca0.77MnO3 exhibits complex phase behavior relevant to colossal magnetoresistance materials.
• Understanding domain coexistence and dynamics is crucial for electronic and magnetic applications.

Purpose of the Study:

• To investigate the coexistence and dynamical interplay of charge-ordered (CO) and charge-disordered (CD) domains in La0.23Ca0.77MnO3.
• To elucidate the structural and dynamical characteristics of these coexisting phases and their relationship with magnetic transitions.

Main Methods:

• High-resolution transmission electron microscopy (HR-TEM) for structural analysis.
• Resistivity measurements to probe phase transitions and dynamics.
• Analysis of domain morphology and orientation relative to superlattice vectors.

Main Results:

• Coexistence of lamellar charge-ordered (CO) and charge-disordered (CD) domains observed below approximately 170 K.
• A CD-monoclinic phase forms within the CO-orthorhombic matrix, with sheetlike morphology perpendicular to the CO superlattice q vector.
• Dynamic competition between CO and CD phases observed between 64 and 130 K, with the CD phase slowly advancing.

Conclusions:

• The study reveals a dynamic coexistence and competition between distinct charge ordering states in La0.23Ca0.77MnO3.
• The observed slow dynamics are linked to magnetic transitions, indicating significant magnetoelastic coupling effects.
• These findings provide insights into the complex phase behavior of manganites and their potential for tunable electronic properties.