Related papers: Order parameter fluctuation effects on current-ind…
Effect of phase fluctuations on superconducting states with anisotropic order parameters is studied in a BCS like lattice model of cuprate superconductors. The degradation of the mean field transition temperature due to phase fluctuations…
The dynamics of the ferromagnetic order parameter in thin magnetic films is strongly affected by the magnetomechanical coupling at certain resonance frequencies. By solving the equation of motion of the coupled mechanical and magnetic…
We present a theory for spin excitations in ferromagnetic metallic manganites and demonstrate that orbital fluctuations have strong effects on the magnon dynamics in the case these compounds are close to a transition to an orbital ordered…
We consider classical spin models of two- and three-dimensional spins with continuous symmetry and investigate the effect of a symmetry-breaking unidirectional quenched disorder on the magnetization of the system. We work in the mean-field…
When an ordered spin system of a given dimensionality undergoes a second order phase transition the dependence of the order parameter i.e. magnetization on temperature can be well-described by thermal excitations of elementary collective…
The influence of correlation effects on the orbital moments for transition metals and their alloys is studied by first-principle relativistic Density Functional Theory in combination with the Dynamical Mean-Field Theory. In contrast to the…
In general, quantum fluctuations are suppressed in ferromagnetic materials because they admit a simple unfrustrated ground state, greatly limiting the scope of phenomena that can be observed in these materials. In this work, we show how…
The Heisenberg nearest neighbour antiferromagnet on the pyrochlore (3D) lattice is highly frustrated and does not order at low temperature where spin-spin correlations remain short ranged. Dzyaloshinsky-Moriya interactions (DMI) may be…
Powder neutron diffraction experiments have been employed to establish the effects of site-selective magnetic dilution in the Sm2MnMnMn4-x Tix O12 A-site columnar ordered quadruple perovskite manganites (x = 1, x = 2 and x = 3). We show…
Ordering by thermal fluctuations is studied for the classical XY antiferromagnet on a checkerboard lattice in zero and finite magnetic fields by means of analytical and Monte Carlo methods. The model exhibits a variety of novel broken…
The effects of high magnetic fields applied perpendicular to the spontaneous ferroelectric polarization on single crystals of BiFeO$_3$ were investigated through magnetization, magnetostriction, and neutron diffraction measurements. The…
We study the effect of order parameter phase fluctuations on the single-particle properties of fermions in the underdoped cuprate superconductors using a phenomenological low-energy theory. We identify the fermion-phase field coupling as…
This study examines the effect of distorted triangular magnetic interactions in the Kagome lattice. Using a Holstein-Primakoff expansion, we determine the analytical solutions for classical energies and the spin-wave modes for various…
Spectra of one-electron and collective excitations in narrow-band ferromagnets with unquenched orbital moments are calculated in various theoretical models. The interaction of spin and orbital excitations with conduction electrons results…
We study kagome lattice antiferromagnets where the effects of easy axis single-ion anisotropy ($D$) dominates over the Heisenberg exchange $J$. For $S \ge 3/2$, virtual quantum fluctuations help lift the extensive classical degeneracy. We…
I consider skyrmionic states in non-centrosymmetric magnets near the ordering temperatures. I show that the interaction between the chiral skyrmions, being repulsive in a broad temperature range, changes into attraction at high…
The effect of thermal fluctuations on the temperature dependence of the topological index C1 of the chiral d+id superconducting phase of a two-dimensional single-band model on a triangular lattice is investigated. Thermal fluctuations are…
We study by Monte Carlo simulations the effect of quenched orientational disorder in systems of interacting classical dipoles on a square lattice. Each dipole can lie along any of two perpendicular axes that form an angle psi with the…
Ensembles of gold nanoparticles present a magnetic behavior which is at odds with the weakly diamagnetic response of bulk gold. In particular, an unusual ferromagnetic order has been unveiled by several experiments. Here we investigate if…
Magnetic phase transitions between ordered phases are often understood on the basis of semi-classical spin models. Deviations from the classical description due to the quantum nature of the atomic spins as well as quantum fluctuations are…