Related papers: Polaron Exchange Model for Ferromagnetic Ordering …
The magnetic susceptibility and spin-spin correlation of the double-exchange model for doped manganites are investigated through the Monte Carlo calculations on the three-dimensional lattice model. Deviations of the susceptibility from the…
We propose two statistical models for description the metal-insulator phase transition coupled with paramagnetic-ferromagnetic phase transition in manganites of the type La_{1-x}Sr_xMnO_3. The first one based on the competition of small…
It is shown that charge transport in substituted manganites (La1/3Sm2/3)0.67Ba0.33-xSrxMnO3 (x = 0.0, 0.1, 0.2 and 0.33) is through polarons which are formed through electron-phonon coupling whose strength determines the mobility of the…
Based on the model combining the spin double exchange and the lattice polaron, we have studied the colossal magnetoresistance phenomena observed in perovskite manganites R_{1-x}A_xMnO_3. First, effects of both the double exchange and the…
In the colossal magnetoresistance manganites polarons have been proposed as the charge carrier state which localizes across the metal-insulator transition. The character of the polarons is still under debate. We present an assessment of…
We report on the optical properties of the hole-doped manganites Nd_{0.7}Sr _{0.3}MnO_{3}, La_{0.7}Ca_{0.3}MnO_{3}, and La_{0.7}Sr_{0.3}MnO_{3}. The low-energy optical conductivity in the paramagnetic-insulating state of these materials is…
The presence of spin-polarized charge carriers in metallic magnets provides a mechanism for spin-lattice interactions mediated by electron-phonon coupling. Here, we present a theory of this mechanism used to estimate its effect on the…
The ferromagnetic Kondo model with classical corespins is studied via unbiased Monte-Carlo simulations. We show that with realistic parameters for the manganites and at low temperatures, the double-exchange mechanism does not lead to phase…
We present a small-but-sizeable magnetic polaron picture where transport at high temperatures is activated while at low temperatures it is band-like. We show that both double exchange and finite bandwidth effects are important to understand…
Polarons - fermionic charge carriers bearing a strong companion lattice deformation - exhibit a natural tendency for self-localization due to the recursive interaction between electrons and the lattice. While polarons are ubiquitous in…
Studying the nature and consequences of electron-phonon interaction in manganites is an area of intense ongoing research. Here, in an attempt to model charge and orbital ordering in manganites displaying C-type antiferromaganetism, we study…
The phase diagram of the multivalent manganites $\rm La_{1-x}Ca_xMnO_3$, in space of temperature and doping $x$, is a challenge for the theoretical physics. It is an important test for the model used to study these compounds and the method…
Transport properties in doped manganites are studied by considering the Simplified double exchange mechanism in the presence of diagonal disorder. It is modelled by a combination the Ising double exchange with Faliccov-Kimball model. In…
We derive an effective Hamiltonian that takes into account the quantum nature of phonons and models cooperative Jahn-Teller effect in the adiabatic regime and at strong electron-phonon coupling in one dimension. Our approach involves…
An introduction is given to the many-body coherent potential approximation (CPA) for the double-exchange (DE) model and the Holstein-DE model, the latter including coupling of the electrons to local phonons as well as to local spins. It is…
The electronic structure of perovskite manganese oxides is investigated in terms of a Kondo lattice model with ferromagnetic Hund coupling and antiferromagnetic exchange between $t_{2g}$-spins using a finite temperature diagonalization…
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…
Polar magnetic states are realized in pseudocubic manganite thin films fabricated on high-index substrates, in which a Jahn-Teller (JT) distortion remains an active variable. Several types of orbital-orders were found to develop large…
We consider the double exchange model at very low densities. The conditions for the formation of self-trapped magnetic polarons are analyzed using an independent polaron model. The issue of phase separation in the low density region of the…
We report on an a $\mu$SR and $^{55}$Mn NMR investigation of the magnetic order parameter as a function of temperature in the optimally doped La$_{5/8}$(Ca$_y$Sr$_{1-y}$)$_{3/8}$MnO$_3$ and in the underdoped La$_{1-x}$Sr$_{x}$MnO$_3$ and…