S. Süllow

Nature of the Spin Dynamics and 1/3 Magnetization Plateau in Azurite

We present a specific heat and inelastic neutron scattering study in magnetic fields up into the 1/3 magnetization plateau phase of the diamond chain compound azurite Cu3(CO3)2(OH)2. We establish that the magnetization plateau is a dimer-monomer state, i.e., consisting of a chain of S=1/2 monomers, which are separated by S=0 dimers on the diamond chain backbone. The effective spin couplings Jmono/kB=10.1(2) K and Jdimer/kB=1.8(1) K are derived from the monomer and dimer dispersions. They are associated to microscopic couplings J1/kB=1(2) K, J2/kB=55(5) K and a ferromagnetic J3/kB=-20(5) K, possibly as result of dz2} orbitals in the Cu-O bonds providing superexchange (SE) pathways with JSE=6.5 K.

Weak ferromagnetism with very large canting in a chiral lattice: Fe(pyrimidine)2Cl2

The transition metal coordination compound Fe(pyrimidine) 2 Cl 2 crystallizes in a chiral lattice, space group I4 1 22 (or I4 3 22). Combined magnetization, Mossbauer spectroscopy, and powder neutron diffraction studies reveal that it is a canted antiferromagnet below T N =6.4 K with an unusually large canting of the magnetic moments of 14° from their general antiferromagnetic alignment, one of the largest reported to date. This results in weak ferromagnetism with a ferromagnetic component of ∼1 μ B . The large canting is due to the interplay between the antiferromagnetic exchange interaction and the local single-ion anisotropy in the chiral lattice. The magnetically ordered structure of Fe(pyrimidine) 2 Cl 2 , however, is not chiral. The implications of these findings for the search of molecule based materials exhibiting chiral magnetic ordering are discussed.

Giant Spin Canting in the S = 1/2 Antiferromagnetic Chain [CuPM(NO~3)~2(H~2O)~2]~n Observed by ^1^3C-NMR

We present a combined experimental and theoretical study on copper pyrimidine dinitrate [CuPM(NO3)2(H2O)2]n, a one-dimensional S=1/2 antiferromagnet with alternating local symmetry. From the local susceptibility measured by NMR at the three inequivalent carbon sites in the pyrimidine molecule we deduce a giant spin canting, i.e., an additional staggered magnetization perpendicular to the applied external field at low temperatures. The magnitude of the transverse magnetization, the spin canting of (52+/-4) degrees at 10 K and 9.3 T, and its temperature dependence are in excellent agreement with exact diagonalization calculations.

High-field magnetization study of the S = 1 2 antiferromagnetic Heisenberg chain [ PM Cu ( NO 3 ) 2 ( H 2 O ) 2 ] n with a field-induced gap

We present a high-field magnetization study of the

Magnetic and crystal structure of azurite Cu3(CO3)2(OH)2as determined by neutron diffraction

S=\frac{1}{2}

The dynamics of azurite Cu3(CO3)2(OH)2 in a magnetic field as determined by neutron scattering

antiferromagnetic Heisenberg chain

A pressure study of the antiferromagnetic phase of FePM2Cl2 (PM = pyrimidine)

[\mathrm{PM}\mathrm{Cu}({\mathrm{NO}}_{3}{)}_{2}({\mathrm{H}}_{2}\mathrm{O}{)}_{2}{]}_{n}.

Magnetoelastic and structural properties of azurite Cu 3 ( CO 3 ) 2 ( OH ) 2 from neutron scattering and muon spin rotation

For this material, as result of the Dzyaloshinskii-Moriya interaction and a staggered g tensor, the ground state is characterized by an anisotropic field-induced spin excitation gap and a staggered magnetization. Our data reveal the qualitatively different behavior in the directions of maximum and zero spin excitation gap. The data are analyzed via exact diagonalization of a linear spin chain with up to 20 sites and on basis of the Bethe ansatz equations, respectively. For both directions we find very good agreement between experimental data and theoretical calculations. We extract the magnetic coupling strength

Electronic Localization and Two-Dimensional Metallic State in UPt2Si2

{J/k}_{B}

Complex Field-Induced States in Linarite PbCuSO4(OH)2 with a Variety of High-Order Exotic Spin-Density Wave States.

along the chain direction to 36.3(5) K and determine the field dependence of the staggered magnetization component