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Muon-spin rotation $(\ensuremath{\mu}\mathrm{SR})$ and torque magnetometry have been used to probe the anisotropy of an untwinned single crystal of ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}.$ The absence of twin planes allows the ratios of all three principal components of the superconducting effective mass tensor to be determined. The values for the in-plane anisotropy are in good agreement with values obtained by other techniques. The out-of-plane anisotropies as measured by $\ensuremath{\mu}\mathrm{SR}$ are also found to be in good agreement with other microscopic measurements, but somewhat lower than those resulting from torque measurements on this and other crystals.

We have measured the diffracted neutron scattering intensities from the square magnetic flux lattice in the perovskite superconductor ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$, which is thought to exhibit $p$-wave pairing with a two-component order parameter. The relative intensities of different flux lattice Bragg reflections over a wide range of field and temperature have been shown to be inconsistent with a single component Ginzburg-Landau theory but qualitatively agree with a two-component $p$-wave Ginzburg-Landau theory.

Muon spin rotation $(\ensuremath{\mu}\mathrm{SR})$ measurements of the magnetic-field distribution $n(B)$ in the vortex state of the oxygen deficient high-${T}_{c}$ superconductor ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{6.60}$ reveal a vortex-lattice melting transition at much lower temperature than that in the fully oxygenated material. The transition is best described by a model in which adjacent layers of ``pancake'' vortices decouple in the liquid phase. In some samples we also observe changes in $n(B)$ which are consistent with a vortex lattice which becomes disordered along the field direction above a crossover field ${B}_{\mathrm{cr}}.$ A transition of this nature has previously been reported in the highly anisotropic superconductor ${\mathrm{Bi}}_{2+x}{\mathrm{Sr}}_{2\ensuremath{-}x}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8+y}.$

We report muon spin rotation $(\ensuremath{\mu}\mathrm{SR})$ measurements on the moving vortex lattice (VL) in the type-II superconductor Pb-In, backed up by small-angle neutron scattering (SANS) observations on the same sample. We observe a motional narrowing of the $\ensuremath{\mu}\mathrm{SR}$ lineshape $p(B)$ and by SANS, alignment of the VL to the direction of vortex motion. We have calculated the $\ensuremath{\mu}\mathrm{SR}$ lineshape expected with a range of orientations of the moving VL. We demonstrate how the new $\ensuremath{\mu}\mathrm{SR}$ results give information on the moving VL which is complementary and consistent with the SANS data.