Weak charge-lattice coupling requires reinterpretation of stripes of charge order in La1-xCaxMnO3.

Coherent optical and acoustic phonon generation correlated with the charge-ordering phase transition in La1−xCaxMnO3

We have observed coherent optical and acoustic phonon generation, which are strongly coupled to the charge-ordering sCOd transition in La1−xCaxMnO3 sx=0.5, 0.58d using femtosecond optical pump-probe spectroscopy. Coherent optical phonons, observed at low temperatures, disappear above the charge-ordering temperature TCO, while coherent acoustic phonons display the opposite behavior, disappearing...

Domain formation and orbital ordering transition in a doped Jahn-Teller insulator.

The ground state of a double-exchange model for orbitally degenerate e(g) electrons with Jahn-Teller lattice coupling and weak disorder is found to be spatially inhomogeneous near half filling. Using a real-space Monte Carlo method we show that doping the half-filled orbitally ordered insulator leads to the appearance of hole-rich disordered regions in an orbitally ordered environment. The dopi...

Investigation of the electronic structure of the charge-ordered phase in epitaxial and polycrystalline La1−xCaxMnO3 (x=0.55,0.67) perovskite manganites

A new spinwave expansion for the ordered Kondo lattice

We present a concise introduction to a new spinwave expansion scheme for magnetically ordered Kondo lattice models. This is motivated by consideration of the ferromagnetically ordered phase of the “double exchange” system La1−xCaxMnO3. A brief overview is given of the consequences of quantum and thermal fluctuation effects for the magnetic properties of the double exchange ferromagnet. INTRODUC...

Local bias induced ferroelectricity in manganites with competing charge and orbital order states.

Perovskite-type manganites, such as Pr1-xCaxMnO3, La1-xCaxMnO3 and La1-xSrxMnO3 solid solutions, are set forth as a case study of ferroelectricity formation mechanisms associated with the appearance of site- and bond-centered orbital ordering which breaks structural inversion symmetry. Even though the observation of macroscopic ferroelectricity may be hindered by the finite conductivity of mang...