Scientific Highlights

In quantum magnetic materials, ordered phases induced by an applied mag- netic field can be described as the Bose-Einstein condensation (BEC) of mag- non excitations. In the strongly frustrated system SrCu₂(BO₃)₂, no clear magnon BEC could be observed, pointing to an alternative mechanism, but the high fields required to probe this physics have remained a barrier to detailed investigation.Here we exploit the first purpose-built high-field neutron scattering facility to measure ...

Understanding the degree to which charge-stripe, spin-stripe, and superconducting orders compete/coexist is paramount for elucidating the microscopic pairing mechanism in the cuprate high-temperature superconductors. We explore the tunability of magnetism, superconductivity, and crystal structure in the stripe phase of the cuprate La_2−xBa_xCuO₄, by employing complementary techniques under compressive uniaxial stress in the CuO₂ plane. Our results show a sixfold increase ...

We report on measurements of the in-plane magnetic penetration depth (λab) in single crystals of Sr₂RuO₄ down to ≃0.015  K by means of muon-spin rotation-relaxation. The linear temperature dependence of λ⁻²_ab for T≲0.7  K suggests the presence of nodes in the superconducting gap. This statement is further substantiated by observation of the Volovik effect, i.e., the reduction of λ⁻²_ab as a function of the applied magnetic field. The experimental zero-field ...

Fifty years after Anderson’s resonating valence-bond proposal, the spin-1/2 triangular-lattice Heisenberg antiferromagnet (TLHAF) remains the ultimate platform to explore highly entangled quantum spin states in proximity to magnetic order. Yb-based delafossites are ideal candidate TLHAF materials, which allow experimental access to the full range of applied in-plane magnetic fields. We perform a systematic neutron scattering study of CsYbSe₂, first proving the Heisenberg character of the interactions and quantifying the second-neighbor coupling.