相关论文: One-Dimensional Quantum Magnetism in the S = 1/2 M…

We have successfully grown sizable single crystals of La_2Cu_{1-z}(Zn,Mg)_zO_4 with up to nearly half of the magnetic Cu sites replaced by non-magnetic Zn and Mg. Neutron scattering, SQUID magnetometry, and complementary quantum Monte Carlo…

Non-magnetic impurities in an S=1/2 Heisenberg antiferromagnetic chain are studied using boundary conformal field theory techniques and finite-temperature quantum Monte Carlo simulations. We calculate the static structure function,…

Inelastic neutron scattering experiments have been carried out on a powder sample of Cu2PO4OH, which consists of diamond-shaped tetramer spin units with S=1/2. We have observed two nearly dispersionless magnetic excitations at E1~12 and…

The proton hyperfine shift K and NMR relaxation rate $1/T_1$ have been measured as a function of temperature in the S=1/2 Heisenberg antiferromagnetic ladder Cu2(C5H12N2)2Cl4. The presence of a spin gap $\Delta \simeq J_\perp-J_\parallel$…

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…

The magnetic properties of $\alpha$-NaFeO$_2$ are studied by neutron diffraction and magnetization measurements. An ordered phase with spins aligned along the b$_hex$ axis exists at low temperatures (T < 4 K). At intermediate temperatures…

We study the magnetic properties of $S=1/2$ antiferromagnetic Heisenberg chains with inhomogeneity of interaction. Using a quantum Monte Carlo method and an exact diagonalization method, we study bond-impurity effect in the uniform $S=1/2$…

We report on the microscopic model of the recently synthesized one-dimensional quantum magnet (NO)Cu(NO3)3. Applying density functional theory band structure calculations, we obtain a leading antiferromagnetic exchange coupling J ~ 200 K,…

Magnetic properties of two and three-dimensional clusters of quantum dots are studied with exact diagonalization of a generalized Hubbard model. We study the weak coupling limit, where the electrons interact only within a quantum dot and…

The antiferromagnetism in $\alpha$-Cu$_3$Mg(OH)$_6$Br$_2$ was studied by magnetic-susceptibility, specific-heat and neutron-diffraction measurements. The crystal structure consists of Cu$^{2+}$ kagome layers with Mg$^{2+}$ ions occupying…

We examine the ground state and the excitations of an one-dimensional Heisenberg spin 1/2 antiferromagnet with alternating dimers and four-spin plaquettes (dimer-plaquette chain). The properties of the system depend on the competing dimer…

We present neutron diffraction, muon spin rotation and pulsed-field magnetometry measurements on the Heisenberg quantum chiral chain [Cu(pym)(H2O)4]SiF6.H2O, which displays a four-fold-periodic rotation of the local environment around the…

We present powder inelastic neutron scattering measurements of the S=1 dimerized antiferromagnet Ba$_3$Mn$_2$O$_8$. The $T=1.4$ K magnetic spectrum exhibits a spin-gap of $\Delta \approx 1.0$ meV and a dispersive spectrum with a bandwidth…

In so-called $j_\mathrm{eff} = 1/2$ systems, including some iridates and ruthenates, the coherent superposition of $t_\mathrm{2g}$ orbitals in the ground state gives rise to hopping processes that strongly depend on the bond geometry.…

We report measurements of the magnetic excitation spectrum of the layered antiferromagnet La2CoO4 by time-of-flight neutron inelastic scattering. In the energy range probed in our experiments (0-250 meV) the magnetic spectrum consists of…

Neutron diffraction and magnetic susceptibility studies of orthorhombic single crystal {\Ksub} confirm the three dimensional (3D) C-type antiferromagnetic (AFM) ordering of the Mn$^{2+}$ moments at $T_{\rm N}=305 \pm 3$ K which is slightly…

Sr$_{3}$ZnIrO$_{6}$ is an effective spin one-half Mott insulating iridate belonging to a family of magnets which includes a number of quasi-one dimensional systems as well as materials exhibiting three dimensional order. Here we present the…

We present the properties of a new organic $S=1$ antiferromagnetic chain system $m$-NO$_2$PhBNO (abbreviated BoNO). In this biradical system two unpaired electrons from aminoxyl groups are strongly ferromagnetically coupled ($|J_\text{FM}|…

The non-centrosymmetric magnetic structure of ErMn$_2$O$_5$ has been shown to be very similar to that of HoMn$_2$O$_5$ (Vecchini {\it et al.}, 2008 Phys. Rev. B {\bf 77} 134434). The magnetic modulation at 25 K has propagation vector $\vec…

The magnetic and thermodynamic properties of spin-1/2 Heisenberg diamond chains are investigated in three different cases: (a) J1, J2, J3>0 (frustrated); (b) J1, J3<0, J2>0 (frustrated); and (c) J1, J2>0, J3<0 (non-frustrated). The density…