Bella Lake

Spin and orbital order in the vanadium spinel MgV2O4

octahedra and a low temperature space group (I4m2) that maintains the mirrorplane symmetry. The magnetic structure that develops below 42K consists of antiferromagneticchains with a strongly reduced moment while inelastic neutron scattering reveals one-dimensionalbehavior and a single band of excitations. The implications of these results are discussed in terms ofvarious orbital ordering scenarios. We conclude that although spin-orbit coupling must be signi cantto maintain the mirror plane symmetry, the trigonal distortion is large enough to mix the 3d levelsleading to a wave function of mixed real and complex orbitals.

Physical realization of a quantum spin liquid based on a complex frustration mechanism

A detailed and systematic study of Ca10Cr7O28 reveals all the hallmarks of spin-liquid behaviour, in spite of the compound’s unusually complex structure.

Ferromagnetically Coupled Shastry-Sutherland Quantum Spin Singlets in (CuCl)LaNb2O7

A thorough crystal structure determination at very low temperature of (CuCl)LaNb₂O₇, originally proposed as a spin-1/2 square-lattice antiferromagnet, is reported thanks to the use of single-crystal x-ray diffraction and powder neutron diffraction. State-of-the-art calculations (maximum entropy method) reveal that (CuCl)LaNb₂O₇ is orthorhombic with Pbam symmetry. First-principles calculations demonstrate that the dominant magnetic interactions are antiferromagnetic between fourth nearest neighbors with a Cu-Cl-Cl-Cu exchange path, which lead to the formation of spin singlets. The two strongest interactions between the singlets are ferromagnetic, which makes (CuCl)LaNb₂O₇ the first system of ferromagnetically coupled Shastry-Sutherland quantum spin singlets.

Investigations of the effect of nonmagnetic Ca substitution for magnetic Dy on spin-freezing in Dy2Ti2O7

Physical properties of partially Ca substituted hole-doped Dy2Ti2O7 have been investigated by ac magnetic susceptibility χ(ac)(T), dc magnetic susceptibility χ(T), isothermal magnetization M(H) and heat capacity C(p)(T) measurements on Dy1.8Ca0.2Ti2O7. The spin-ice system Dy2Ti2O7 exhibits a spin-glass type freezing behavior near 16 K. Our frequency dependent χ(ac)(T) data of Dy1.8Ca0.2Ti2O7 show that the spin-freezing behavior is significantly influenced by Ca substitution. The effect of partial nonmagnetic Ca(2+)u2009substitution for magnetic Dy(3+) is similar to the previous study on nonmagnetic isovalent Y(3+) substituted Dy(2-x)Y(x) Ti2O7 (for low levels of dilution), however the suppression of spin-freezing behavior is substantially stronger for Ca than Y. The Cole-Cole plot analysis reveals semicircular character and a single relaxation mode in Dy1.8Ca0.2Ti2O7 as for Dy2Ti2O7. No noticeable change in the insulating behavior of Dy2Ti2O7 results from the holes produced by 10% Ca(2+) substitution for Dy(3+) ions.

Experimental observation of Bethe strings

Almost a century ago, string states—complex bound states of magnetic excitations—were predicted to exist in one-dimensional quantum magnets. However, despite many theoretical studies, the experimental realization and identification of string states in a condensed-matter system have yet to be achieved. Here we use high-resolution terahertz spectroscopy to resolve string states in the antiferromagnetic Heisenberg–Ising chain SrCo2V2O8 in strong longitudinal magnetic fields. In the field-induced quantum-critical regime, we identify strings and fractional magnetic excitations that are accurately described by the Bethe ansatz. Close to quantum criticality, the string excitations govern the quantum spin dynamics, whereas the fractional excitations, which are dominant at low energies, reflect the antiferromagnetic quantum fluctuations. Today, Bethe’s result is important not only in the field of quantum magnetism but also more broadly, including in the study of cold atoms and in string theory; hence, we anticipate that our work will shed light on the study of complex many-body systems in general.

Quantum spin chain as a potential realization of the Nersesyan-Tsvelik model

It is well established that long-range magnetic order is suppressed in magnetic systems whose interactions are low dimensional. The prototypical example is the

Kondo lattice heavy fermion behavior in CeRh2Ga2

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Softened magnetic excitations in the s = 3/2 distorted triangular antiferromagnet α-CaCr2O4.

Heisenberg antiferromagnetic chain (

Investigation of the spin-1 honeycomb antiferromagnet BaNi2V2O8 with easy-plane anisotropy

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Optical Floating-Zone Growth of Large Single Crystal of Spin Half Dimer Sr3Cr2O8

HAFC) whose ground state is quantum critical. In real