Related papers: The Phase Separation Scenario for Manganese Oxides
We have investigated the change in entropy with direct measurements of heat flow as a function of magnetic field at fixed temperatures across the entire phase diagram of the phase-separated (PS) compound…
We present a continuum model for doped manganites which consist of two species of quantum spin 1/2 fermions interacting with classical spin fields. The phase structure at zero temperature turns out to be considerably rich: antiferromagnetic…
Phase separation has been observed by several different experiments and it is believed to be closely related with the physics of cuprates but its exactly role is not yet well known. We propose that the onset of pseudogap phenomenon or the…
In addition to Anderson and Mott localization, intrinsic phase separation has long been advocated as the third fundamental mechanism controlling the doping-driven metal-insulator transitions. In electronic system, where charge neutrality…
The influence of quenched disorder on the competition between ordered states separated by a first-order transition is investigated. A phase diagram with features resembling quantum-critical behavior is observed, even using classical models.…
We study the consequences of Coulomb interactions on a system undergoing a putative first order phase transition. In two dimensions (2D), near the critical density, the system is universally unstable to the formation of new intermediate…
Magnetoresistance (MR) and magnetization (d.c and a.c) measurements have been carried out on the manganites, (La0.7-2xEux)(Ca0.3Srx)MnO3 (0.05<x<0.15), in the temperature range of 5K-320K. At 5K, an unusually large MR of almost 98% is…
The three dimensional perovskite manganites in the range of hole-doping $x > 0.5$ are studied in detail using a double exchange model with degenerate $e_g$ orbitals including intra- and inter-orbital correlations and near-neighbour Coulomb…
We employ diagrammatic Monte Carlo simulations to establish criteria for the stability of line-node semimetals in the presence of Coulomb interactions. Our results indicate a phase transition to a chiral insulating state that occurs at a…
Quantum phase transitions between the magnetically ordered and disordered states are studied for the two-dimensional antiferromagnetic quantum spin systems with ladder, plaquette, and mixed-spin structures. Starting with properly chosen…
Large scale Monte Carlo simulation results for the two-orbital model for manganites, including Jahn-Teller lattice distortions, are here presented. At hole density x=1/4 and in the vicinity of the region of competition between the…
Understanding the underlying mechanism and phenomenology of colossal magnetoresistance in manganites has largely focused on atomic and nanoscale physics such as double exchange, phase separation, and charge order. Here we consider a more…
At half doping, the ground state of three-dimensional manganite perovskite oxides like R$_{1-x}$Ca$_x$MnO$_3$, where R is a trivalent ion such as La, Pr, etc, is still unclear. Many experimental findings agree better with the combined…
We study the theoretical model of a ferromagnetic semiconductor as a system of randomly distributed Ising spins with a long-range exchange interaction. Using the density-of-states approach, we analytically obtain the magnetic susceptibility…
We study the phase diagram of a mixture of Bose-Einstein condensate and a two-component Fermi gas. In particular, we identify the regime where the homogeneous system becomes unstable against phase separation. We show that, under proper…
From Raman spectroscopy, magnetization, and thermal-expansion on the system La2/3(Ca1-xSrx)1/3MnO3, we have been able to provide a quantitative basis for the heterogeneous electronic model for manganites exhibiting colossal…
Using valence band photoemission we have demonstrated the presence of a pseudogap in the near Fermi level electronic spectrum of some of the mixed phase compositions of Sm$_{1-x}$Ca$_x$MnO$_3$ system. The pseudogap was found to grow in size…
We present a detailed study of a model for strain-induced metal-insulator phase coexistence in perovskite manganites. Both nanoscale and mesoscale inhomogeneities are self-consistently described using atomic scale modes and their associated…
We present a detailed magnetic study of the perovskite manganite Pr0.7Ca0.3MnO3 at low temperatures including magnetization and a.c. susceptibility measurements. The data appear to exclude a conventional spin glass phase at low fields,…
The metal-insulator transition, and the associated magnetic transition, in the colossal magnetoresistance (CMR) regime of the one-orbital model for manganites is here studied using Monte Carlo (MC) techniques. Both cooperative oxygen…