Related papers: Low-frequency spin dynamics in the orthorombic pha…
We derive an effective Hamiltonian for spin dynamics of fluctuating smectic stripes from the t-J model in the weak coupling limit t >> J. Besides the modulation of spin magnitude, the high energy hopping term would induce a low-energy…
The magnetic structure of (La${}_{1.8}$Eu${}_{0.2}$)CuO${}_4$ has been studied by magnetization measurements of single crystals, which show antiferromagnetic long-range order below $T_N$ = 265 K and a structural phase transition at $T_s$ =…
We study the spin-wave spectrum and the spin-flop transitions in La_2CuO_4 in a uniform magnetic field at zero temperature. Using the non-linear sigma-model, we show that a field applied along the orthorhombic b direction leads to a…
While the dominant magnetic interaction in La$_2$CuO$_4$ is superexchange between nearest-neighbor Cu moments, the pinning of the spin direction depends on weak anisotropic effects associated with spin-orbit coupling. The symmetry of the…
We present an effective field theory method to analyze, in a very general way, models defined over small-world networks. Even if the exactness of the method is limited to the paramagnetic regions and to some special limits, it provides,…
Using soft x-ray absorption spectroscopy and magnetic circular dichroism at the Co-$L_{2,3}$ edge we reveal that the spin state transition in LaCoO$_{3}$ can be well described by a low-spin ground state and a triply-degenerate high-spin…
Measurements of the static magnetization, susceptibility and ESR of Gd spin probes have been performed to study the properties of antiferromagnetically ordered La_{2-x-y}Eu_ySr_xCuO_4 (x less or equal 0.02) with the low temperature…
We consider a model of one dimensional spin-1 bosons with repulsive density-density interactions and antiferromagnetic exchange. We show that the low energy effective field theory is given by a spin-charge separated theory of a…
The electronic interlayer transport of the lightly doped antiferromagnet La1.79Eu0.2Sr0.01CuO4 has been studied by means of magneto-resistance measurements. The central problem addressed concerns the differences between the electronic…
In the context of an ever-expanding experimental and theoretical interest in the magnetization dynamics of mesoscopic magnetic structures, both in the classical and quantum regimes, we formulate a low energy field theory for the linear…
The normal phase of the high-$T_c$ cuprates is apparently not described by Fermi liquid theory. It has been proposed that a dynamically generated gauge field must appear in the effective field theory. Even a simple spinon-gauge system is…
The low-temperature series for the free energy density, pressure, magnetization and susceptibility of cubic ideal ferromagnets in weak external magnetic fields are discussed within the effective Lagrangian framework up to three loops. The…
The problem of characterizing low-temperature spin dynamics in antiferromagnetic spin chains has so far remained elusive. We reinvestigate it by focusing on isotropic antiferromagnetic chains whose low-energy effective field theory is…
Non-linear magnetization dynamics is essential for the operation of many spintronics devices. For microwave assisted switching of magnetic elements the low field regime is of particular interest. In addition a large number of experiments…
This work is devoted to the logical proof of the Goodenough and Khomskii idea of the existence of spin-orbit transitions in transition magnetic crystals. In agreement with the basics of the Landau theory of phase transitions the…
A model Hamiltonian representing the Cu spins in La$_2$CuO$_4$ in its low-temperature body-centred orthorhombic phase, that includes both spin-orbit generated Dzyaloshinskii-Moriya interactions and interplanar exchange, is examined within…
The magnetic properties of CuO encompass several contemporary themes in condensed matter physics, including quantum magnetism, magnetic frustration, magnetically-induced ferroelectricity and orbital currents. Here we report polarized and…
Low energy spin excitations were investigated in the static stripe phase of La_{2-x}Sr_xCuO_4 using elastic and inelastic neutron scattering on single crystals. For x = 1/8 in which long-range static stripe order exists, an energy gap of…
A magnetic susceptibility which decreases with decreasing temperature is observed in all $CuO_2$ based superconductors with less than optimal doping. We propose that in $La_{2-x} Sr_x CuO_4$ this is due to antiferromagnetic ordering which…
We summarize our recent theoretical studies on the spin dynamics in the normal state of the metallic cuprates. The contrasting wave vector dependence of the dynamical spin structure factor $S({\bf q}, \omega )$ in LaSrCuO and YBaCuO systems…