相关论文: Phase separation, percolation and giant isotope ef…
Recent computational studies of models for manganese oxides have revealed a rich phase diagram, not anticipated in early calculations in this context performed in the 1950's and 60's. In particular, the transition between the…
The chemical influence in the phase separation phenomenon that occurs in perovskite manganites is discussed by means of ab initio calculations. Supercells have been used to simulate a phase separated state, that occurs at Ca concentrations…
The properties of phase-separated systems, e.g. manganites, close to a I order phase transition between charge-ordered insulator and ferromagnetic metal, are usually described by the percolation picture. We argue that the correlated…
Spin-state transitions, observed in many transition metal compounds containing Co$^{3+}$ and Fe$^{2+}$, may occur with the change of temperature, pressure, but also with doping, in which case the competition of single-site effects and…
A macroscopic phase separation, in which ferromagnetic clusters are observed in an insulating matrix, is sometimes observed, and believed to be essential to the colossal magnetoresistive (CMR) properties of manganese oxides. The application…
We report a detailed study of the electric transport and magnetic properties of the LaNdCaMnO manganite system. Substitution of LaIII by smaller NdIII ions, reduces the mean ionic radius of the A site ion. We have studied samples in the…
The complex lanthanide doping of electron manganites results in enhancement of various phase separation effects in physical properties of these compounds. Selecting Ca0.8Sm0.16Nd0.04MnO3 as a model case we show that the first order…
The theory of first order density-driven phase transitions with frustration due to the long range Coulomb (LRC) interaction develop on paper I of this series is applied to the following physical systems: i) the low density electron gas ii)…
The study of the manganese oxides, widely known as manganites, that exhibit the ``Colossal'' Magnetoresistance (CMR) effect is among the main areas of research within the area of Strongly Correlated Electrons. After considerable theoretical…
A "minimal model" of the Kondo-lattice type is used to describe a competition between the localization and metallicity in doped manganites and related magnetic oxides with Jahn-Teller ions. It is shown that the number of itinerant charge…
We propose a dielectrophoresis model for phase-separated manganites. Without increase of the fraction of metallic phase, an insulator-metal transition occurs when a uniform electric field applied across the system exceeds a threshold value.…
High resolution neutron diffraction shows that the mesoscopic separation into ferromagnetic (FM) and antiferromagnetic (AFM) phases and the FM transition temperature T_C in the perovskite manganite (La_{1-y}Pr_{y})_{0.7}Ca_{0.3}MnO_3…
We investigated electrical and magnetic properties of the electron-doped manganites Ca1-xSmxMnO3 (0<x<0.2). Our results indicate the possibility of phase separation in electron doped manganites. The compounds with x = 0.13-0.15 show unusual…
Giant oxygen isotope effects observed in colossal magnetoresistance manganites are investigated by employing the combined model of the double exchange and interacting lattice polaron mechanism. We have shown that the isotope effects on $…
A recent vast experimental and theoretical effort in manganites has shown that the colossal magnetoresistance effect can be understood based on the competition of charge-ordered and ferromagnetic phases. The general aspects of the…
A possible mechanism of electronic phase separation in the systems with orbital ordering is analyzed. We suggest a simple model taking into account an interplay between the delocalization of charge carriers introduced by doping and the…
An analysis of the properties of half-doped manganites is presented. We build up the phase diagram of the system combining a realistic calculation of the electronic properties and a mean field treatment of the temperature effects. The…
The effect of giant dielectric permittivity due to phase separation accompanied by charged inhomogeneities in low-doped manganites is discussed. The effect appears in the vicinity of the second-order magnetic phase transition and is caused…
This paper is an informal review of the present status of the computational studies of models for manganites that recently reported the existence of phase separation at low temperatures (S. Yunoki et al., Phys. Rev. Lett. 80, 845 (1998) and…
We consider the nanoscale electronic phase separation in a wide class of different materials, mostly in strongly correlated electron systems. The phase separation turns out to be quite ubiquitous manifesting itself in different situations,…