The phase diagram of the spin-density-wave metamagnet Sr3Ru2O7

Sr3Ru2O7 is an unusual layered oxide metamagnetic metal. It has been know for some time that the application of a large magnetic field (~8 T) perpendicular to the RuO2 planes induces a new "A" phase at low temperatures (T<1.5K). The A phase has thermodynamic and electronic transport anomalies which define its boundaries. It also has anisotropic electronic properties. We have recently used WISH to identify the A phase as spin density wave (SDW) order and discover a neighbouring "B" phase at slightly higher field. Here we propose to: (i) map out the temperature/field phase boundary of the B phase (which is difficult by other techniques); (ii) determine whether electronic anomalies for magnetic fields applied within the RuO2 planes also correspond to SDW order.

Sr3Ru2O7是一种罕见的层状氧化物变磁金属。长期以来人们便已发现，在垂直于RuO₂晶面的方向施加约8特斯拉的强磁场时，会在低温（T<1.5K）下诱导出全新的“A相”。A相存在热力学与电子输运反常行为，这些反常行为界定了该相的相界范围，同时该相还表现出各向异性的电子特性。我们近期借助WISH仪器，将A相确认为自旋密度波（SDW）有序态，并在略高的磁场区间发现了相邻的“B相”。本研究计划开展以下工作：(i) 测绘B相的温度-磁场相界（该测量借助其他技术难以实现）；(ii) 探究当磁场施加于RuO₂晶面内时，观测到的电子反常行为是否同样对应自旋密度波有序态。