Related papers: Spin Waves and Magnetic Exchange Interactions in C…
We present specific-heat and neutron-scattering results for the \emph{S}=1/2 quantum antiferromagnet (dimethylammonium)(3,5-dimethylpyridinium)CuBr$_4$. The material orders magnetically at \emph{T}$_N$=1.99(2)\,K, and magnetic excitations…
Since the discovery of the metallic antiferromagnetic (AF) ground state near superconductivity in iron-pnictide superconductors, a central question has been whether magnetism in these materials arises from weakly correlated electrons, as in…
Using elastic neutron scattering, we evidence a commensurate antiferromagnetic Cu(2) order (AF) in the superconducting (SC) high-$\rm T_c$ cuprate $\rm YBa_2(Cu_{1-y}Co_y)_3O_{7+\delta}$ (y=0.013, $\rm T_c$=93 K). As in the Co-free system,…
The topological properties of massive and massless fermionic quasiparticles have been intensively investigated over the past decade in topological materials without magnetism. Recently, the bosonic analogs of such quasiparticles arising…
Neutron scattering, with its ability to measure the crystal structure, the magnetic order, and the structural and magnetic excitations, plays an active role in investigating various families of Fe-based high-Tc superconductors. Three…
The magnetic excitations of the iron pnictides are explained within a degenerate double-exchange model. The local-moment spins are coupled by superexchanges $J_1$ and $J_2$ between nearest and next-nearest neighbors, respectively, and…
The very intriguing antagonistic interplay of antiferromagnetism (AF) and superconductivity (SC), recently discovered in high-temperature superconductors, is studied in the framework of a microscopic theory. We explain the surprisingly…
Magnetic spin fluctuations is one candidate to produce the bosonic modes that mediate the superconductivity in the ferrous superconductors. Up until now, all of the LaOFeAs and BaFe2As2 structure types have simple commensurate magnetic…
We report quantum oscillation measurements in SrFe2As2 - which is an antiferromagnetic parent of the iron-arsenide family of superconductors - known to become superconducting under doping and the application of pressure. The magnetic field…
Unconventional superconductivity (SC) is said to occur when Cooper pair formation is dominated by repulsive electron-electron interactions, so that the symmetry of the pair wavefunction is other than isotropic s-wave. The strong, on-site,…
We report an inelastic neutron scattering study of the spin waves of the one-dimensional antiferromagnetic spin ladder compound RbFe$_2$Se$_3$. The results reveal that the products, $SJ$'s, of the spin $S$ and the magnetic exchange…
Neutron scattering measurements were performed to investigate magnetic excitations in a single-crystal sample of the ternary iron arsenide BaFe2As2, a parent compound of a recently discovered family of Fe-based superconductors. In the…
High-temperature superconductivity (HTSC) in copper oxides emerges on a layered CuO2 plane when an antiferromagnetic Mott insulator is doped with mobile hole carriers. We review extensive studies of multilayered copper oxides by…
We use inelastic neutron scattering to show that superconducting (SC) rubidium iron selenide Rb0.82Fe1.68Se2 exhibits antiferromagnetic (AF) spin excitations near the in-plane wave vector Q = (PI, 0) identical to that for iron arsenide…
We use unpolarized and polarized inelastic neutron scattering to study low-energy spin excitations in NaFeAs, which exhibits a tetragonal-to-orthorhombic lattice distortion at $T_s\approx 58$ K followed by a collinear antiferromagnetic (AF)…
BaFe2As2 is the parent compound of the '122' iron arsenide superconductors and crystallizes with the tetragonal ThCr2Si2 type structure, space group I4/mmm. A spin density wave transition at 140 K is accompanied by a symmetry reduction to…
Using an atomistic spin model, we have simulated spin wave injection and propagation into antiferromagnetic IrMn from an exchange coupled CoFe layer. The spectral characteristics of the exited spin waves have a complex beating behavior…
Understanding the magnetoresistance (MR) of a magnetic material forms the basis for uncovering the orbital mechanisms and charge-spin interactions in the system. Although the parent state of iron-based high-temperature superconductors,…
Magnetic correlations in the paramagnetic phase of CaFe2As2 (T_N=172 K) have been examined by means of inelastic neutron scattering from 180 K (~ 1.05 T_N) up to 300 K (~1.8 T_N). Despite the first-order nature of the magnetic ordering,…
Recent inelastic neutron scattering experiments in CeIn$_{3}$ and CePd$_{2}$Si$_{2}$ single crystals measured spin wave excitations at low temperatures. These two heavy fermion compounds exhibit antiferromagnetic long-range order, but a…