Emergence of Superconductivity on the Border of Antiferromagnetic Order in RbMn6Bi5 under High Pressure:A New Family of Mn-Based Superconductors

We report the discovery of superconductivity on the border of antiferromagnetic order in a quasi-one-dimensional material RbMn₆Bi₅ via measurements of resistivity and magnetic susceptibility under high pressures.Its phase diagram of temperature versus pressure resembles those of many magnetism-mediated superconducting systems.With increasing pressure,its antiferromagnetic ordering transition with T_N=83 K at ambient pressure is first enhanced moderately and then s...     

High pressure synthesis and characterization of the pyrochlore Dy_2Pt_2O_7:A new spin ice material

The cubic pyrochlore Dy2Pt2O7 was synthesized under 4 GPa and 1000℃ and its magnetic and thermodynamic properties were characterized by DC and AC magnetic susceptibility and specific heat down to 0.1 K.We found that Dy2Pt2O7 does not form long-range magnetic order,but displays characteristics of canonical spin ice such as Dy2Pt2O7,including(1)a large effective moment 9.64μB close to the theoretical value and a small positive Curie-Weiss temperatureθCW=+0.77 K signaling a dominant ferromagnetic interaction among the Ising spins;(2)a saturation moment ~4.5μB being half of the total moment due to the local<111>Ising anisotropy;(3)thermally activated spin relaxation behaviors in the low(~1 K)and high(~20 K)temperature regions with different energy barriers and characteristic relaxation time;and most importantly,(4)the presence of a residual entropy close to Pauling’s estimation for water ice.