Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada.
Phys Rev Lett. 2009 Nov 27;103(22):227202. doi: 10.1103/PhysRevLett.103.227202. Epub 2009 Nov 25.
Neutron scattering measurements show the ferromagnetic XY pyrochlore Yb2Ti2O7 to display strong quasi-two-dimensional (2D) spin correlations at low temperature, which give way to long range order (LRO) under the application of modest magnetic fields. Rods of scattering along 111 directions due to these 2D spin correlations imply a magnetic decomposition of the cubic pyrochlore system into decoupled kagome planes. A magnetic field of approximately 0.5 T applied along the [110] direction induces a transition to a 3D LRO state characterized by long-lived, dispersive spin waves. Our measurements map out a complex low temperature-field phase diagram for this exotic pyrochlore magnet.
中子散射测量表明，铁磁 XY 型方钴矿 Yb2Ti2O7 在低温下表现出强烈的准二维（2D）自旋关联，在适度磁场的作用下，这些关联会导致长程有序（LRO）。由于这些 2D 自旋关联，在 111 方向上产生的散射杆意味着立方方钴矿系统分解为解耦的 kagome 平面。沿 [110] 方向施加约 0.5 T 的磁场会诱导转变为具有长寿命、弥散自旋波的 3D LRO 态。我们的测量为这种奇异的方钴矿磁体描绘了一个复杂的低温场相图。
