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

Lamellar charge ordered (CO) and charge disordered (CD) phase separation at low temperatures in La0.23Ca0.77MnO3 was firstly revealed using transmission electron microscopy (TEM). The in-situ TEM observations showed the evolution of the CO-CD phase separation with changed temperatures. Electron diffraction found the different crystal structures of CO and CD phases. Magnetism measurements in La0.23Ca0.77MnO3 indicate two magnetic phase transitions that interestingly coincide with two transition temperatures found in the resistivity relaxation curves. The TEM dark field images observed the dynamic competition between CO and CD phases and the observation is consistent with that in transport properties. The finding here suggests that the CO-CD phase coexistence in this manganite at certain temperature range is driven by magnetoelastic effects rather than being dictated by disorder.