Antiferromagnetic order and its interplay with superconductivity in CaK(Fe1-xMn)As.

The magnetic order for several compositions of CaK(Fe1-xMn)Ashas been studied by nuclear magnetic resonance (NMR), Mössbauer spectroscopy, and neutron diffraction. Our observations for the Mn-doped 1144 compound are consistent with the hedgehog spin vortex crystal (hSVC) order which has previously been found for Ni-dopedCaKFe4As4. The hSVC state is characterized by the stripe-type propagation vectors(π0)and(0π)just as in the doped 122 compounds.

A Low-Temperature Structural Transition in Canfieldite, AgSnS, Single Crystals.

Canfieldite, AgSnS, is a semiconducting mineral notable for its high ionic conductivity, photosensitivity, and low thermal conductivity. We report the solution growth of large single crystals of AgSnS of mass up to 1 g from a ternary Ag-Sn-S melt. On cooling from high temperature, AgSnS undergoes a known cubic (4̅3) to orthorhombic (2) phase transition at ≈460 K.

Magnetic ordering and structural distortion in a PrFeAsO single crystal studied by neutron and x-ray scattering.

We report the magnetic ordering and structural distortion in PrFeAsO crystals, the basis compound for one of the oxypnictide superconductors, using high-resolution x-ray diffraction, neutron diffraction, and x-ray resonant magnetic scattering (XRMS). We find the structural tetragonal-to-orthorhombic phase transition at , the AFM phase transition of the Fe moments at , and the Pr AFM phase transition at . Combined high-resolution neutron diffraction and XRMS show unambiguously that the Pr moments point parallel to the longer orthorhombic axis and order antiferromagnetically along the axis but ferromagnetically along the and directions in the stripelike AFM order.

Magnetic crystalline-symmetry-protected axion electrodynamics and field-tunable unpinned Dirac cones in EuInAs.

Knowledge of magnetic symmetry is vital for exploiting nontrivial surface states of magnetic topological materials. EuInAs is an excellent example, as it is predicted to have collinear antiferromagnetic order where the magnetic moment direction determines either a topological-crystalline-insulator phase supporting axion electrodynamics or a higher-order-topological-insulator phase with chiral hinge states. Here, we use neutron diffraction, symmetry analysis, and density functional theory results to demonstrate that EuInAs actually exhibits low-symmetry helical antiferromagnetic order which makes it a stoichiometric magnetic topological-crystalline axion insulator protected by the combination of a 180 rotation and time-reversal symmetries: [Formula: see text].

Magnetic-field effects on the fragile antiferromagnetism in YbBiPt.

We present neutron-diffraction data for the cubic-heavy-fermion YbBiPt that show broad magnetic diffraction peaks due to the fragile short-range antiferromagnetic (AFM) order persist under an applied magnetic-field . Our results for and a temperature of show that magnetic diffraction peak can be described by the same two-peak line shape found for below the Néel temperature of . Both components of the peak exist for , which is well past the AFM phase boundary determined from our new resistivity data.