Related papers: Double Exchange in a Magnetically Frustrated Syste…
We investigate the zero-temperature phase diagram and spin-wave properties of a double exchange magnet with on-site Hubbard repulsion. It is shown that even within a simple Hartree -- Fock approach this interaction (which is often omitted…
We study the transport properties of frustrated itinerant magnets comprising localized {\it classical} moments, which interact via exchange with the conduction electrons. Strong frustration stabilizes a liquidlike spin state, which extends…
We theoretically study the magnetic excitations in a frustrated two-leg spin-ladder system, in which antiferromagnetic exchange interactions act on the nearest-neighbor and next-nearestneighbor bonds in the leg direction, and on the…
The resistivity around the ferromagnetic transition temperature in the double exchange model is studied by the Schwinger boson approach. The spatial spin correlation responsible for scattering of conduction electrons are taken into account…
Dynamic behavior of a quantum Heisenberg ferromagnet in the presence of a periodically oscillating magnetic field has been analyzed by means of the effective field theory with two spin cluster. The dynamic equation of motion has been…
In this work, we study a biquadratic Heisenberg model with coupled orbital degree of freedom using Monte Carlo simulation in order to investigate the phase transitions in iron-based superconductors. The antiferro-quadrupolar state, which…
Motivated by systems that can be seen as composed of two frustrated sublattices combined into a less frustrated total lattice, we study the double-exchange model with nearest-neighbor (NN) and next--nearest-neighbor (NNN) couplings on the…
We studied ferromagnetism in the one-dimensional Hubbard model with doubly degenerate atomic orbitals by means of the density-matrix renormalization-group method and obtained the ground-state phase diagrams. It was found that ferromagnetism…
The spin-$1/2$ Heisenberg chain with a ferromagnetic first-neighbor exchange coupling $J_1$ and an antiferromagnetic second-neighbor $J_2$ has a Haldane dimer ground state with an extremely small spin gap. Thus, the ground state is readily…
Motivated by the recent suggestion of anisotropic effective exchange interactions between Mn spins in Ga$_{1-x}$Mn$_x$As (arising as a result of spin-orbit coupling), we study their effects in diluted Heisenberg spin systems. We perform…
We study the ground-state properties of weakly frustrated Heisenberg ferrimagnetic chains with nearest and next-nearest neighbor antiferromagnetic exchange interactions and two types of alternating sublattice spins S_1 > S_2, using 1/S…
We study the ferromagnetism due to orbital degeneracy in the Hubbard model in infinite dimensions. The model contains the intraorbital repulsion $U$, the interorbital repulsion $U^\prime$, the exchange $J$ (Hund coupling) and the pair…
We study classical Heisenberg antiferromagnets with uniaxial exchange anisotropy and a cubic anisotropy term on simple cubic lattices in an external magnetic field using ground state considerations and extensive Monte Carlo simulations. In…
We study the competition between ferromagnetic double exchange (DE) and nearest-neighbour antiferromagnetic exchange in CMR materials. Towards this end, a single site mean field theory is proposed which emphasizes the hopping-mediated…
We study a frustrated two-leg spin ladder with alternate isotropic Heisenberg and Ising rung exchange interactions, whereas, interactions along legs and diagonals are Ising-type. All the interactions in the ladder are anti-ferromagnetic in…
The ground state of the $S=1/2$ $J_{1}-J_{1}$ Heisenberg model on the 2D square lattice with arbitrary signs of exchange constants is considered. States with different spin long-range order types (antiferromagnetic checkerboard, stripe,…
We consider a two-layer Heisenberg antiferromagnet which can be either in the N\'{e}el-ordered or in the disordered phase at $T=0$, depending on the ratio of the intra- and interlayer exchange constants. We reduce the problem to an…
We use the coupled cluster method implemented to high orders of approximation to investigate the frustrated spin-$\frac{1}{2}$ $J_{1}$--$J_{2}$--$J_{3}$ antiferromagnet on the honeycomb lattice with isotropic Heisenberg interactions of…
The possibility of a zero temperature, altermagnetic instability in anisotropic two dimensional electron systems in the diffusive regime is analyzed, in the presence and absence of spin-orbit coupling. Allowing for ferromagnetism, a phase…
Applying linear response and the magnetic force theorem in correlated density functional theory, the inter-sublattice exchange constants of antiferromagnetic Eu are calculated and found to vanish near the pressure of P$_c$=82 GPa, just…