Related papers: Theory of the Ordered Phase in A-site Antiferromag…
In spinels ACr2O4 (A=Mg, Zn) realisation of the classical pyrochlore Heisenberg antiferromagnet model is complicated by a strong spin-lattice coupling: the extensive degeneracy of the ground state is lifted by a magneto-structural…
A theoretical description is presented for low-temperature magnetic-field induced three-dimensional (3D) ordering transitions in strongly anisotropic quantum antiferromagnets, consisting of weakly coupled antiferromagnetic spin-1/2 chains…
This paper discusses the ground state of quantum spins interacting via Heisenberg antiferromagnetic exchange, in two dimensional lattices having several different local environments. In unfrustrated lattices, when a N\'eel type order…
A model for a Heisenberg antiferromagnet on a pyrochlore lattice with exchange and dipole-dipole interactions is studied via mean-field theory. In treating the dipoles by use of the Ewald method, a soft (critical) mode with a unique…
By using ab initio methods on different levels we study the magnetic ground state of (finite) atomic wires deposited on metallic surfaces. A phenomenological model based on symmetry arguments suggests that the magnetization of a…
Magnetic multipoles have been recognized as order parameters characterizing magnetic structure in solids. Recently, magnetic octupoles have been proposed as the order parameters of time-reversal-symmetry breaking centrosymmetric…
Easy axis antiferromagnets are robust against external magnetic fields of moderate strength. Spin reorientations in strong fields can provide an insight into more subtle properties of antiferromagnetic materials, which are often hidden by…
MnSi is an itinerant magnet which at low temperatures develops a helical spin density wave. Under pressure it undergoes a transition into an unusual partially ordered state whose nature is debated. Here we propose that the helical spin…
We investigated the magnetic phase diagram of single crystals of SrNdFeO$_{4}$ by measuring the magnetic properties, the specific heat and the dielectric permittivity. The system has two magnetically active ions, Fe$^{3+}$ and Nd$^{3+}$.…
The search for new quantum phases, especially in frustrated magnets, is central to modern condensed matter physics. One of the most promising places to look is in rare-earth pyrochlore magnets with highly-anisotropic exchange interactions,…
We explore the magnetic phases in a Kondo lattice model on the geometrically frustrated Shastry-Sutherland lattice at metallic electron densities, searching for noncollinear and noncoplanar spin textures. Motivated by experimental…
Partially disordered antiferro (PDA) magnetism (in which one of the three magnetic ions in a triangular network remains magnetically disordered), has been known commonly among geometrically frustrated insulating materials. The one-third…
In this paper we obtain an exact periodic solution for the system of equations of state corresponding to the spiral phase of crystalline ordering. We used method of integral rational basis of invariants to construct an inhomogeneous Landau…
We present a theoretical analysis of the temperature-magnetic field-concentration phase diagram of the multiferroic Mn$_{1-x}$M$_{x}$WO$_{4}$ (M=Fe, Zn, Mg), which exhibits three ordered phases, with collinear and non-collinear…
Our polycrystalline sample study on the Yb-based chalcogenide spinels $A$Yb$_2$$X_4$ ($A =$ Cd, Mg, $X =$ S, Se) has revealed frustrated magnetism due to the antiferromagnetically coupled Heisenberg spin on the pyrochlore lattice. Our…
The antiferromagnetic Heisenberg model on an anisotropic kagome lattice may be a good minimal model for real magnetic systems as well as a limit from which the isotropic case can be better understood. We therefore study the nearest-neighbor…
We study magnetic order in the Heisenberg antiferromagnet on the checkerboard lattice, a two-dimensional version of the pyrochlore network with strong geometric frustration. By employing the semiclassical (1/S) expansion we find that…
The iron-based high temperature superconductors exhibit a rich phase diagram reflecting a complex interplay between spin, lattice, and orbital degrees of freedom [1-4]. The nematic state observed in many of these compounds epitomizes this…
We attribute the structural phase transition (SPT) in the parent compounds of the iron pnictides to orbital ordering. Due to the anisotropy of the $d_{xz}$ and $d_{yz}$ orbitals in the $xy$ plane, a ferro-orbital ordering makes the…
Polarized and unpolarized neutron diffraction measurements have been carried out to investigate the iron magnetic order in undoped NdOFeAs. Antiferromagnetic order is observed below 141(6) K, which is in close proximity to the structural…