Low-temperature NMR studies of solid hydrogen at reduced ortho concentrations $X<55%$ are interpreted in terms possible quadrupolar glass phases which the molecules frozen into random configurations. The is an extension concept dipolar spins introduced by Edwards and Anderson.

Measurements are reported of NMR linewidth, $\frac{1}{{T}_{2}}$, for $^{3}\mathrm{He}$ atoms adsorbed on Grafoil at 1 K various quantities gas adsorbed. The data show three well-defined regions corresponding to a two-dimensional fluid, solid, and region where second layer is forming. A sharp minimum in ${T}_{2}$ gives precise indication monolayer completion. theory tunneling the solid presented.

Confined Helium Helium-3 ( 3 He) has superfluid phases closely related to topological insulators and superconductors. In geometrical confinement, He is expected support exotic excitations, but its phase diagram largely unknown, as such measurements are experimentally challenging. Levitin et al. (p. 841 ) confine in a slab geometry of defined height use nuclear magnetic resonance probe. As predicted by theory, the authors find that confinement stabilizes some across larger portion with...

The heat capacity and magnetization of a fluid 3He monolayer adsorbed on graphite plated with bilayer HD have been measured in the temperature range 1-60 mK. Approaching density at which solidifies into sqrt[7]xsqrt[7] commensurate solid, we observe an apparent divergence effective mass corresponding to T=0 Mott-Hubbard transition between 2D Fermi liquid magnetically disordered solid. observations are consistent Brinkman-Rice-Anderson-Vollhardt scenario for metal-insulator transition. We...

Two-dimensional helium-3 (3He) provides a simple model for the experimental investigation of emergence quantum complexity in strongly correlated Fermi system. We have observed two-dimensional, two-band heavy-fermion behavior bilayer films 3He atoms when adsorbed on surface graphite preplated by solid 4He. Thermodynamic measurements this system showed that relevant control parameter is total density film. The can be driven toward critical point at which effective mass appears to diverge,...

The nuclear magnetic susceptibility of $^{3}\mathrm{He}$ adsorbed on the surface graphite, plated with a monolayer solid $^{4}\mathrm{He}$, has been measured at densities less than 0.055 \AA{} $^{\mathrm{\ensuremath{-}}2}$ and temperatures down to 6 mK. A temperature-independent is observed low temperatures, which strongly enhanced over ideal-gas value, due quasiparticle interactions. inferred Landau-Fermi-liquid parameters allow comparison microscopic theories interacting Fermi systems.

The general theory of nuclear magnetic relaxation in homogeneous adsorbed systems is developed a way which takes account the specific features two-dimensional motion. It shown that reduced dimensionality has effect decreasing times from their naively expected values by as much few orders magnitude, and causing T1 T2 to be unequal even presence fast atomic close agreement with observed helium-3.

In superfluid $^3$He-B confined in a slab geometry, domain walls between regions of different order parameter orientation are predicted to be energetically stable. Formation the spatially-modulated stripe phase has been proposed. We $^3$He 1.1 $\mu$m high microfluidic cavity and cooled it into B at low pressure, where is predicted. measured surface-induced distortion with NMR, sensitive formation domains. The results rule out phase, but consistent 2D modulated order.

We describe here the design and performance of a current sensing noise thermometer using low Tc DC SQUID as front end amplifier. The is used to measure thermal in resistor temperature then obtained from Nyquist formula. fast, absolute precise usable over wide range below 4.2 K, principle down well 1 mK. excellent energy sensitivity SQUID, operated at fixed temperature, enables use relatively large resistor, mΩ range. This requires short averaging times when measuring spectrum fluctuations....

Measurements of the magnetization and heat capacity second layer ${}^{3}\mathrm{He}$ films adsorbed on graphite indicate that evolution exchange from antiferromagnetic to ferromagnetic arises a tuning competing processes. At certain coverages coexistence an with is clear manifestation, predicted by theory, frustration. anomaly system well described series expansions for 2D Heisenberg ferromagnet triangular lattice.

We report measurements of the nuclear magnetic susceptibility monolayer two-dimensional solid formed by $^{3}\mathrm{He}$ adsorbed on graphite plated with two atomic layers HD. A low-density is observed, consistent a \ensuremath{\surd}7 \ifmmode\times\else\texttimes\fi{} registered structure, which exhibits large antiferromagnetic exchange. distinct cusp in observed near 1 mK, suggestive phase transition. The evolution this and other features surface density discussed.

Measurements of the nuclear magnetic susceptibility multilayer films 3He adsorbed on graphite plated with a monolayer 4He are reported for surface densities up to 0.27 Å-2 and temperatures in range (6÷600) mK. The coverage dependence exchange constant has been measured; this is antiferromagnetic when second layer first solidifies becomes ferromagnetic formation fluid overlayer. second-layer solid density evolves stepwise fashion increasing coverage, while overlayer shows structure associated...

${T}_{1}$ measurements have been performed on the solid phase of helium-3 adsorbed Grafoil. A theory has developed to interpret these data basis hypothesis a single correlation time for exchange-induced spin motion. We infer that relaxation is mediated by internuclear dipolar interaction. show how ${T}_{1}$-minima together with exact moment and hydrodynamic calculations may be used approximate spectral functions over their whole range. Thus we obtain numerical values exchange frequency all...

We report the determination of magnetic phase diagram heavy fermion metal YbRh\textsubscript{2}Si\textsubscript{2} in fields up to 70\,mT applied perpendicular crystallographic c-axis. By a combination heat capacity, magneto-caloric, and magneto-resistance measurements we map two antiferromagnetic phases: electronic AFM1 below 70\,mK electro-nuclear AFM2 1.5\,mK. The extend into microkelvin regime explore quantum transitions this system. demonstrate how hyperfine interaction significantly...

We previously reported the discovery of a two-dimensional <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mmultiscripts><a:mrow><a:mi>He</a:mi></a:mrow><a:mprescripts/><a:none/><a:mrow><a:mn>4</a:mn></a:mrow></a:mmultiscripts></a:mrow></a:math> supersolid; state with intertwined density wave and superfluid order, observed in second layer <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"...

The nuclear magnetic susceptibility of submonolayer $^{3}\mathrm{He}$ films adsorbed on a graphite substrate has been measured for temperatures between 6 and 800 mK. Three distinct surface-density regimes are identified fractional monolayer coverages below perfect registry. These appear to be fluid phase with some atoms localized by heterogeneity, solid-fluid coexistence region, registered solid defects. ${\mathit{T}}_{2}$ values inferred from NMR linewidth measurements also reported.

The $B$ phase of superfluid $^{3}\mathrm{He}$ is a three-dimensional time-reversal invariant topological superfluid, predicted to support gapless Majorana surface states. We confine into thin nanofluidic slab geometry. In the presence weak symmetry-breaking magnetic field, we have observed two possible states confined $^{3}\mathrm{He}\mathrm{\text{\ensuremath{-}}}B$ manifold, through small tipping angle NMR response. Large nonlinear has allowed identification order parameter these and...

A 3He nuclear Zeeman maser is fully described. Macroscopic equations of motion for the magnetisation in cell are derived from exact solutions Schrodinger's equation and solved by numerical approximate analytical methods. Results obtained an experimental agree closely with theory. Applications to magnetometry a gyroscope discussed.

We have measured the heat capacity of second layer solid in a ${}^{3}\mathrm{He}$ film adsorbed on surface graphite to temperatures below 1 mK, regime where nuclear exchange interaction is antiferromagnetic. The temperature dependence data described by high series expansions for 2D Heisenberg antiferromagnet triangular lattice. There no evidence phase transition down $J/3$. Comparison with $J$ inferred from magnetization provides measure frustration due competing antiferromagnetic and...