Related papers: A low-dimensional spin S = 1/2 system at the quant…
We present the results of measurements of the dc-magnetic susceptibility chi(T) and the 23Na-NMR response of Na_{0.70}CoO_{2} at temperatures between 50 and 340 K. The chi(T) data suggest that for T > 75 K, the Co ions adopt an effective…
We study a bandwidth controlled Mott metal-insulator transition (MIT) between a Fermi liquid metal and a quantum spin-liquid insulator at half-filling in three dimensions (3D). Using a slave rotor approach, and incorporating gauge field…
Previous heat-capacity measurements of our group had shown the possible existence of an anomalous quantum phase containing the zero-point vacancies (ZPVs) in 2D $^{3}$He. The system is monolayer $^{3}$He adsorbed on graphite preplated with…
Na4Ir3O8 is a unique case of a hyperkagome 3D corner sharing triangular lattice which can be decorated with quantum spins. It has spurred a lot of theoretical interest as a spin liquid candidate. We present a comprehensive set of NMR data…
We have synthesized the novel material Na_2IrO_3 and studied its structure, transport, magnetic, and thermal properties using powder x-ray diffraction (PXRD), electrical resistivity, isothermal magnetization M versus magnetic field H,…
We have performed AC susceptibility and DC magnetic relaxation measurements on the spin ice system Dy$_2$Ti$_2$O$_7$ down to 0.08 K. The relaxation time of the magnetization has been estimated below 2 K down to 0.08 K. The spin dynamics of…
We report on the results of 23Na NMR in the honeycomb lattice magnet Na2Co2TeO6 which has been nominated as a Kitaev material. Measurements of magnetic shift and width of the NMR line as functions of temperature and magnetic field show that…
Based on experimental 59Co-NMR data in the temperature range between 0.1 and 300 K, we address the problem of the character of the Co 3d-electron based magnetism in Na0.7CoO2. Temperature dependent 59Co-NMR spectra reveal different Co…
We report that the major features in the temperature dependence of dc and ac magnetization of a well-known spin-chain compound, Ca3Co2O6, which has been known to exhibit two complex magnetic transitions due to geometrical frustration (one…
In a magnetic field, spin-ladders undergo two zero-temperature phase transitions at the critical fields Hc1 and Hc2. An experimental review of static and dynamical properties of spin-ladders close to these critical points is presented. The…
An $^{17}$O NMR measurement was performed on nonoriented polycrystalline Na$_{0.35}$CoO$_2 \cdot y$H$_2$O with superconducting (SC) transition temperature $T_\text{c} = 4.6$ K. A weak temperature dependence was observed in the Knight shift…
We have shown that the observed large reduction of the effective moment in Na2V3O7 may be caused by conventional crystal-field interactions and the intra-atomic spin-orbit coupling of the V4+ ion. The fine discrete electronic structure of…
Tb2Ti2O7 is a pyrochlore antiferromagnet that has dynamical spins and only short-range correlations even at 50 mK; the lowest temperature explored so far, which is much smaller than the scale set by the Curie-Weiss temperature T_{CW}~14 K.…
In this paper we demonstrate the application of high magnetic fields to study the magnetic properties of low dimensional spin systems. We present a case study on the series of 2-leg spin-ladder compounds…
We present a comprehensive study of single crystals of Na2Co2TeO6, a putative Kitaev honeycomb magnet, focusing on its low-temperature phase behaviors. A new thermal phase transition is identified at 31.0 K, below which the system develops…
We report on {23}Na NMR studies of a honeycomb lattice antiferromagnet Na2Ni2TeO6 by {23}Na nuclear spin-echo techniques. The {23}Na nuclear spin-lattice relaxation rate 1/{23}T_1 exhibits critical divergence near a Neel temperature T_N =…
The magnetic behaviour of the low-dimensional Vanadium-oxides Sr2V3O9 and Ba2V3O9 was investigated by means of magnetic susceptibility and specific heat measurements. In both compounds, the results can be very well described by an S=1/2…
By quenched-randomly mixing local units of different spatial dimensionalities, we have studied Ising spin-glass systems on hierarchical lattices continuously in dimensionalities 1 =< d =< 3. The global phase diagram in temperature,…
Magnetic properties of the spin-3/2 Heisenberg system Cr2BP3O12 are investigated by magnetic susceptibility chi(T) measurements, electron spin resonance, neutron diffraction, and density functional theory (DFT) calculations, as well as…
We report on 7Li NMR studies of a spin S = 3/2 triangular lattice antiferromagnet LiCrO2 (Neel temperature TN = 62 K) in the paramagnetic state by using the free-induction decay of 7Li nuclear magnetization. We observed critical divergence…