Related papers: Dynamical Structure Factor in Cu Benzoate and othe…
Magnetic properties of the antiferromagnet Zn$_{0.15}$Cu$_{1.85}$V$_2$O$_7$ (ZnCVO) have been thoroughly investigated on powder and single-crystal samples. The crystal structure determination using powder x-ray and neutron diffraction…
Inelastic neutron scattering was used to study a quantum S=1/2 antiferromagnetic Heisenberg system-Bis(2-amino-5-fluoropyridinium) Tetrachlorocuprate(II). The magnetic excitation spectrum was shown to be dominated by long-lived excitations…
The notion of a quasiparticle, such as a phonon, a roton, or a magnon, is used in modern condensed matter physics to describe an elementary collective excitation. The intrinsic zero-temperature magnon damping in quantum spin systems can be…
Only 3% hole doping by Li is sufficient to suppress the long-range antiferromagnetic order in La2CuO4. Spin dynamics in such a disordered state was investigated with measurements of the dynamic magnetic structure factor S(omega,q), using…
We report measurements of the two-magnon states in a dimerized antiferromagnetic chain material, copper nitrate (Cu(NO3)2*2.5D2O). Using inelastic neutron scattering we have measured the one and two magnon excitation spectra in a large…
We study the field dependence of the antiferromagnetic spin-1/2 Heisenberg model on the square lattice by means of exact diagonalizations. In a first part, we calculate the spin-wave velocity, the spin-stiffness, and the magnetic…
Inelastic neutron scattering measurements demonstrate that the magnetic interactions in antiferromagnetic LaFeAsO are two-dimensional. Spin wave velocities within the Fe layer and the magnitude of the spin gap are similar to the…
By inelastic neutron scattering, we have analyzed the magnetic correlations in the paramagnetic metallic region of the series Ca(2-x)Sr(x)RuO(4), 0.2<=x<=0.62. We find different contributions that correspond to 2D ferromagnetic fluctuations…
Magnetic excitations in copper pyrimidine dinitrate, a spin-1/2 antiferromagnetic chain with alternating $g$-tensor and Dzyaloshinskii-Moriya interactions that exhibits a field-induced spin gap, are probed by means of pulsed-field electron…
Unlike most quantum systems which rapidly become incoherent as temperature is raised, strong correlations persist at elevated temperatures in $S=1/2$ dimer magnets, as revealed by the unusual asymmetric lineshape of their excitations at…
We have analyzed magnetic-field-dependent small-angle neutron scattering (SANS) data of soft magnetic two-phase nanocomposite ferromagnets in terms of a recent micromagnetic theory for the magnetic SANS cross section [D. Honecker and A.…
We discuss the magnetic excitations of well-ordered stripe and checkerboard phases, including the high energy magnetic excitations of recent interest and possible connections to the "resonance peak" in cuprate superconductors. Using a…
We report measurements of the two-magnon states in a dimerized antiferromagnetic chain material, copper nitrate (\QTR{group}{Cu(NO$_{3}$)$_{2}\cdot 2.5$D$_{2}$O}). Using inelastic neutron scattering, we have studied the one- and two-magnon…
We present an inelastic neutron scattering investigation of Li2CuO2 detecting the long sought quasi-1D magnetic excitations with a large dispersion along the CuO2-chains studied up to 25 meV. The total dispersion is governed by a…
We have studied the two-dimensional S=1/2 square-lattice antiferromagnet $Cu(pz)_2(ClO_4)_2$ using inelastic neutron scattering and series expansion calculations. We show that the presence of antiferromagnetic next-nearest neighbor…
Using an electron spin resonance spectrometer covering a wide range of frequency and magnetic field, we have measured the low energy excitations of the S=1/2 tetragonal antiferromagnets, Sr_{2}CuO_{2}Cl_{2} and Sr_{2}Cu_{3}O_{4}Cl_{2}. Our…
Neutron scattering measurements have been performed on the S=1/2 quasi-one-dimensional system Sr_{14-x}Y_{x}Cu_{24}O_{41}, which has both simple chains and two-leg ladders of copper ions. We observed that when a small amount of yttrium is…
We investigate the critical properties of the $S=1/2$ bond-alternating spin chain with a next-nearest-neighbor interaction in magnetic fields. By the numerical calculation and the exact solution based on the effective Hamiltonian, we show…
The quasi-two-dimensional Heisenberg spin $S=1/2$ dimer system bis(2-amino-5-fluoro-pyridinium) tetrachlorocuprate(II) is studied by means of inelastic neutron scattering, calorimetry and nuclear magnetic resonance (NMR) experiments. In the…
Making the assumption that high energy fermions exist in the two dimensional spin-1/2 Heisenberg antiferromagnet we present predictions based on the pi-flux ansatz for the dynamic structure factor when the antiferromagnet is subject to a…