Nuclear magnetic resonance (NMR) study of the high magnetic field (H) part of the Bose-Einstein condensed (BEC) phase of the quasi one-dimensional (quasi-1D) antiferromagnetic quantum spin-chain compound NiCl2- 4SC(NH2)2 (DTN) was performed. We precisely determined the phase boundary, Tc(H), down to 40 mK, the critical boson density, nc(Tc), and the absolute value of the BEC order parameter Sp at very low temperature (T = 0.12 K). All results are accurately reproduced by numerical quantum Monte Carlo simulations of a realistic 3D model Hamiltonian. Approximate analytical predictions based on 1D Tomonaga- Luttinger liquid description are found to be precise for Tc(H), but less so for Sp(H), which is more sensitive to the strength of 3D couplings, in particular close to the critical field. A mean-field treatment, based on the Hartree-Fock- Popov description, is found to be valid only up to nc = 4% (T < 0.3 K), while for higher nc boson interactions appear to modify the density of states.

•We applied the magnetoresistance (MR) characterization in UTBB FDSOI.•A Coulomb scattering-free behavior was shown in low Vg for long devices at 300K.•The additional scatterings associated with HK/MG were visible with RCS or SOP.•A mobility improvement induced by back biasing effect was demonstrated.

Nuclear magnetic resonance (NMR) and transport measurements have been performed at high magnetic fields and low temperatures in a series of n-type Bi2Se3 crystals. In low-density samples, a complete spin polarization of the electronic system is achieved, as observed from the saturation of the isotropic component of the Bi-209 NMR shift above a certain magnetic field. The corresponding spin splitting, defined in the phenomenological approach of a 3D electron gas with a large (spin-orbit-induced) effective g factor, scales as expected with the Fermi energy independently determined by simultaneous transport measurements. Both the effective electronic g factor and the "contact" hyperfine coupling constant are precisely determined. The magnitude of this latter reveals a nonnegligible s character of the electronic wave function at the bottom of the conduction band. Our results show that the bulk electronic spin polarization can be directly probed via NMR and pave the way for future NMR investigations of the electronic states in Bi-based topological insulators.

Based on high-field (31)P nuclear magnetic resonance experiments and accompanying numerical calculations, it is argued that in the frustrated S=1/2 ladder compound BiCu(2)PO(6) a field-induced soliton lattice develops above a critical field of μ(0)H(c1)=20.96(7) T. Solitons result from the fractionalization of the S=1, bosonlike triplet excitations, which in other quantum antiferromagnets are commonly known to experience Bose-Einstein condensation or to crystallize in a superstructure. Unlike in spin-Peierls systems, these field-induced quantum domain walls do not arise from a state with broken translational symmetry and are triggered exclusively by magnetic frustration. Our model predicts yet another second-order phase transition at H(c2)>H(c1), driven by soliton-soliton interactions, most likely corresponding to the one observed in recent magnetocaloric and other bulk measurements.

Advanced planar MOSFET and FinFET transistors on SOI have been characterized under high magnetic field. The geometrical magnetoresistance stands as the most accurate and indisputable technique for mobility measurements. Our results show that this method is also effective in both planar (FD-SOI) and vertical (FinFET) transistors with ultrathin body. For the first time, we apply the magnetoresistance for evaluating not only the properties of separate channels, but also their interaction mechanisms. Unconventional mobility curves with multi-branch aspect are recorded when two or more channels coexist. They are explained by the variations in effective field and centroid of the inversion charge. A marked difference is observed between front and back channels as well as between planar and FinFET devices.

By means of nuclear spin-lattice relaxation rate T(1)(-1), we follow the spin dynamics as a function of the applied magnetic field in two gapped quasi-one-dimensional quantum antiferromagnets: the anisotropic spin-chain system NiCl(2)-4SC(NH(2))(2) and the spin-ladder system (C(5)H(12)N)(2)CuBr(4). In both systems, spin excitations are confirmed to evolve from magnons in the gapped state to spinons in the gapless Tomonaga-Luttinger-liquid state. In between, T(1)(-1) exhibits a pronounced, continuous variation, which is shown to scale in accordance with quantum criticality. We extract the critical exponent for T(1)(-1), compare it to the theory, and show that this behavior is identical in both studied systems, thus demonstrating the universality of quantum-critical behavior.

We report results of V-51 NMR experiments on a high-quality powder sample of volborthite Cu3V2O7(OH)(2)center dot 2H(2)O, a spin-1/2 Heisenberg antiferromagnet on a distorted kagome lattice. Following the previous experiments in magnetic fields B below 12 T, the NMR measurements have been extended to higher fields up to 31 T. In addition to the two already known ordered phases (phases I and II), we found a new high-field phase (phase III) above 25 T, at which a second magnetization step has been observed. The transition from the paramagnetic phase to the antiferromagnetic phase III occurs at 26 K, which is much higher than the transition temperatures from the paramagnetic to the lower field phases I (B < 4.5 T) and II (4.5 < B < 25 T). At low temperatures, two types of the V sites are observed with different relaxation rates and line shapes in phase III as well as in phase II. Our results indicate that both phases II and III exhibit a heterogeneous spin state consisting of two spatially alternating Cu spin systems, one of which exhibits anomalous spin fluctuations contrasting with the other showing a conventional static order. The magnetization of the latter system exhibits a sudden increase upon entering into phase III, resulting in the second magnetization step at 26 T. We discuss the possible spin structure in phase III.

Competition with magnetism is at the heart of high-temperature superconductivity, most intensely felt near a vortex core. To investigate vortex magnetism we have developed a spatially resolved probe based upon NMR spin-lattice-relaxation spectroscopy. With this approach we have found a spin-density wave associated with the vortex core in Bi2Sr2CaCu2O8+y, similar to checkerboard patterns in the local density of electronic states reported from scanning tunneling microscope experiments. We have determined both the spin-modulation amplitude and decay length from the vortex core in fields up to H = 30 T.

Competition with magnetism is at the heart of high temperature superconductivity, most intensely felt near a vortex core. To investigate vortex magnetism we have developed a spatially resolved probe using nuclear magnetic resonance. Our spin-lattice-relaxation spectroscopy is spatially resolved both within a conduction plane as well as from one plane to another. With this approach we have found a spin-density wave associated with the vortex core in Bi_2Sr_2CaCu_2O_8+δ, which is expected from scanning tunneling microscope observations of "checkerboard" patterns in the local density of electronic states.[1] We determine both the spin-modulation amplitude and decay length from the vortex core in fields up to H=30 T.

If vortex cores within a superconductor can trap electrostatic charge, the cores will experience a repulsive Coulomb interaction. Evidence from NMR measurements indeed suggests that above some threshold magnetic field, the Abrikosov vortex lattice becomes unstable. It has been predicted that superconducting vortices should be electrically charged and that this effect is particularly enhanced for high-temperature superconductors1,2. Hall effect3 and nuclear magnetic resonance (NMR) experiments4 suggest the existence of charge accumulation in the vortex core, but the effects are small and the interpretation controversial. Here we show that the Abrikosov vortex lattice, characteristic of the mixed state of superconductors, will become unstable at a sufficiently high magnetic field if there is charge trapped on the vortex core. Our NMR measurements of the magnetic fields generated by vortices in Bi2Sr2CaCu2O8+y single crystals5 provide evidence for an electrostatically driven vortex lattice reconstruction with the magnitude of charge on each vortex pancake of ∼2×10−3e, depending on doping, in line with theoretical estimates1,6.

Nuclear magnetic resonance (NMR) measurements have been performed on single crystals of Ba1−xKxFe2As2 (x=0, 0.45) and CaFe2As2 grown from Sn flux. The Ba-based pnictide crystals contain significant amounts of Sn in their structure, ∼1%, giving rise to magnetic impurity effects evident in the NMR spectrum and in the magnetization. Our experiments show that the large impurity magnetization is broadly distributed on a microscopic scale, generating substantial magnetic field gradients. There is a concomitant 20% reduction in the transition temperature, which is most likely due to magnetic electron scattering. We suggest that the relative robustness of superconductivity (x=0.45) in the presence of severe magnetic inhomogeneity might be accounted for by strong spatial correlations between impurities, such as clustering on the coherence length scale.

We have found that high quality crystals of Bi(2)Sr(2)CaCu(2)O(8+delta) (Bi-2212) have intrinsic magnetic defects that depend on oxygen doping. Our (17)O nuclear magnetic resonance spectra provide evidence that local moments form in the CuO(2) plane in both normal and superconducting states. We suggest that these magnetic impurities are related to the electronic disorder that scanning tunneling microscopy experiments identify with the oxygen dopant atoms.

The ^17O NMR spectra of Bi_2Sr_2CaCu_2O_8+δ (Bi-2212) single crystals were measured in the temperature range from 4 K to 200 K and magnetic fields from 3 to 29 T, reported here principally at 8 T. The NMR linewidth of the oxygen in the CuO_2 plane was found to be magnetically broadened with the temperature dependence of a Curie law where the Curie coefficient decreases with increased doping. This inhomogeneous magnetism is an impurity effect intrinsic to oxygen doping and persists unmodified into the superconducting state.

Rare-Earth (RE) doped glasses are promising candidates for laser and other opto-electronic applications. The optical properties of the RE doped glasses depend on the symmetry and environment of the RE ion in the host glass and hence its structure. We have studied Nd3+ doped 30Na(2)O-(70-x)B2O3-xNd(2)O(3) glasses with various Nd3+ concentrations (x=0,0.1,0.5,1 mol%) using B-11 NMR. In this paper we have presented a method of estimating the crystal field splitting of the RE ion using B-11 Nuclear Spin-Lattice Relaxation (NSLR) time measurements in these systems as a function of temperature in the range 100-4.2 K. Details of the magnetization recovery fit, theory of B-11 relaxation time are discussed in terms of possible relaxation mechanisms in the presence of a RE ion. We found that the relaxation can be explained using a two-level system (TLS) model for x=0 and the Orbach process for other samples. The magnetization recovery is observed to fit better to a single exponential model in all the samples as evident from the statistical analysis of the fit. The crystal field splitting (Delta) estimated from our studies are found to be around 100 cm(-1), in agreement with other Nd3+-doped systems reported in the literature.

NMR measurements have been performed on single crystals of Ba1 xKxFe2As2 (x = 0, 0.45) and CaFe2As2 grown from Sn ux. The Ba-based pnictide crystals contain signicant amounts of Sn in their structure, 1%, giving rise to magnetic impurity eects evident in the NMR spectrum and in the magnetization. Our experiments show that the large impurity magnetization is broadly distributed on a microscopic scale, generating substantial magnetic eld gradients. There is a concomitant 20% reduction in the transition temperature which is most likely due to magnetic electron scattering. We suggest that the relative robustness of superconductivity (x = 0:45) in the presence of severe magnetic inhomogeneity might be accounted for by strong spatial correlations between impurities on the coherence length scale.