Recent theoretical and experimental findings suggest the long-known but not well understood low temperature resistance plateau of SmB6 may originate from protected surface states arising from a topologically non-trivial bulk band structure having strong Kondo hybridization. Yet others have ascribed this feature to impurities, vacancies, and surface reconstructions. Given the typical methods used to prepare SmB6 single crystals, flux and floating-zone procedures, such ascriptions should not be taken lightly. We demonstrate how compositional variations and/or observable amounts of impurities in SmB6 crystals grown using both procedures affect the physical properties. From X-ray diffraction, neutron diffraction, and X-ray computed tomography experiments we observe that natural isotope containing (SmB6) and doubly isotope enriched (154Sm11B6) crystals prepared using aluminum flux contain co-crystallized, epitaxial aluminum. Further, a large, nearly stoichiometric crystal of SmB6 was successfully grown using the float-zone technique; upon continuing the zone melting, samarium vacancies were introduced. These samarium vacancies drastically alter the resistance and plateauing magnitude of the low temperature resistance compared to stoichiometric SmB6. These results highlight that impurities and compositional variations, even at low concentrations, must be considered when collecting/analyzing physical property data of SmB6. Finally, a more accurate samarium-154 coherent neutron scattering length, 8.9(1) fm, is reported.

We report the discovery of a field driven transition from a single-q to multi-q spin density wave (SDW) in the tetragonal heavy fermion compound CeAuSb_{2}. Polarized along c, the sinusoidal SDW amplitude is 1.8(2)μ_{B}/Ce for T≪T_{N}=6.25(10)  K with a wave vector q_{1}=(η,η,1/2) [η=0.136(2)]. For H∥c, harmonics appearing at 2q_{1} evidence a striped magnetic texture below μ_{∘}H_{1}=2.78(1)  T. Above H_{1}, these are replaced by coupled harmonics at q_{1}+q_{2}=(2η,0,0)+c^{*} until μ_{∘}H_{2}=5.42(5)  T, where satellites vanish and magnetization nonlinearly approaches saturation at 1.64(2)μ_{B}/Ce for μ_{∘}H≈7  T.

We report the discovery of incommensurate magnetism near quantum criticality in CeNiAsO through neutron scattering and zero field muon spin rotation. For T < TN1 = 8.7(3) K, a second order phase transition yields an incommensurate spin density wave with wave vector k = (0.44(4), 0, 0). For T < TN2 = 7.6(3) K, we find co-planar commensurate order with a moment of 0.37(5) µB, reduced to 30 % of the saturation moment of the | ± 1 2 Kramers doublet ground state, which we establish through inelastic neutron scattering. Muon spin rotation in CeNiAs1−xPxO shows the commensurate order only exists for x ≤ 0.1 so we infer the transition at xc = 0.4(1) is between an incommensurate longitudinal spin density wave and a paramagnetic Fermi liquid. arXiv:1707.09645v2 [cond-mat.str-el]