Related papers: Multiple phase transitions and high-field quadrupo…

The phase diagram of the Heisenberg ferromagnetic model in the presence of a magnetic random field (we have used bimodal distribution) of spin S=1/2 (quantum case) and $S=\infty $ (classical case) on a simple cubic lattice is studied within…

We have studied the antiferromagnetic order -- disorder transition occurring at $T=0$ in a 2-layer quantum Heisenberg antiferromagnet as the inter-plane coupling is increased. Quantum Monte Carlo results for the staggered structure factor…

We explore the effects of noncommuting applied fields on the ground-state ordering of the quasi-one-dimensional spin-1/2 XY-like antiferromagnet Cs2CoCl4 using single-crystal neutron diffraction. In zero field interchain couplings cause…

Within the four-loop $\ve$ expansion, we study the critical behavior of certain antiferromagnets with complicated ordering. We show that an anisotropic stable fixed point governs the phase transitions with new critical exponents. This is…

We consider 2D Heisenberg antiferromagnets on a triangular lattice with spatially anisotropic interactions in a high magnetic field close to the saturation. We show that this system possess rich phase diagram in field/anisotropy plane due…

Motivated by the magnetic properties of the spin-chain compounds LiCuSbO$_4$$\equiv$LiSbCuO$_4$ and Rb$_2$Cu$_2$Mo$_3$O$_{12}$, we study the ground state of the Heisenberg chain with dimerized nearest-neighbor ferromagnetic (FM)($J_1,…

Polarized and unpolarized neutron scattering experiments on the frustrated ferromagnetic spin-1/2 chain LiCuVO4 show that the phase transition at HQ of 8 Tesla is driven by quadrupolar fluctuations and that dipolar correlations are…

We study isotropic antiferromagnetic Heisenberg chains coupled by antiferromagnetic Ising interaction as an effective spin model for the ytterbium aluminum perovskite YbAlO$_3$. Using the density-matrix renormalization group (DMRG) method…

We present a systematic study of the anisotropic spin-1/2 Heisenberg model in staggered magnetic fields in two dimensions (2D). To mimic real materials, we consider a system of coupled, antiferromagnetic chains, whose interchain interaction…

The phase diagram of weakly coupled $XXZ$ chains in a transverse magnetic field is studied using the mean-field approximation for the interchain coupling and known exact results for an effective one-dimensional model. Results are applied to…

We present the magnetic phase diagram of a spin-1/2 chain antiferromagnet Sr$_2$CuO$_3$ studied by ultrasound phase-sensitive detection technique. We observe an enhanced effect of external magnetic field on the ordering temperature of the…

Motivated by the magnetic phase transition of a proximate Kitaev system $\alpha$-RuCl$_3$ in the presence of a magnetic field, we study the simplest but essential quantum spin model with the ferromagnetic nearest neighboring (NN) Kitaev…

Characteristics of magnetic transitions in NpTGa$_5$ with T=Co, Ni, Rh are explained in a unified way with use of a crystalline electric field (CEF) model of localized 5$f^4$ electrons. The model takes a CEF doublet and a singlet as local…

High-field phase diagram of a chiral-lattice antiferromagnet Sr(TiO)Cu4(PO4)4 is studied by means of the ultrasound, dielectric, and magnetocaloric-effect measurements. These experimental techniques reveal two new phase transitions at high…

We investigate the stability of the multipolar orderings in $f$-electron material CeCoSi based on a self-consistent mean-field calculation for the effective localized model. This material has two ordered phases in the temperature-pressure…

Ordering of the geometrically frustrated two-dimensional Heisenberg antiferromagnet on a pyrochlore slab is studied by Monte Carlo simulations. The model is expected to serve as a reference system of SrCrGaO compound studied extensively. In…

A two-dimensional Heisenberg model with random antiferromagnetic nearest-neighbor exchange is studied using quantum Monte Carlo techniques. As the strength of the randomness is increased, the system undergoes a transition from an…

Using the coupled cluster method we study the phase diagram of the spin-1/2 Heisenberg antiferromagnet on a honeycomb lattice with nearest-neighbor exchange coupling $J_{1}>0$ and frustrating next-nearest-neighbor coupling $J_{2} \equiv…

The phase diagram of the spin-1/2 Heisenberg antiferromagnet on an anisotropic triangular lattice of weakly coupled chains, a model relevant to Cs2CuCl4, is investigated using a renormalization group analysis, which includes marginal…

Coupled frustrated spin-1/2 chains in high magnetic fields described within the ferro- antiferromagnetic J1-J2 Heisenberg model are studied by the DMRG, the hard core boson, and the spin wave theory approaches. Multipolar phases related to…