Scheie Allen, Kindervater Jonas, Zhang Shu, Changlani Hitesh J, Sala Gabriele, Ehlers Georg, Heinemann Andre, Tucker Gregory S, Koohpayeh Seyed M, Broholm Collin
Institute for Quantum Matter, Johns Hopkins University, Baltimore, MD 21218;
Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218.
Proc Natl Acad Sci U S A. 2020 Nov 3;117(44):27245-27254. doi: 10.1073/pnas.2008791117. Epub 2020 Oct 23.
We use neutron scattering to show that ferromagnetism and antiferromagnetism coexist in the low T state of the pyrochlore quantum magnet [Formula: see text] While magnetic Bragg peaks evidence long-range static ferromagnetic order, inelastic scattering shows that short-range correlated antiferromagnetism is also present. Small-angle neutron scattering provides direct evidence for mesoscale magnetic structure that we associate with metastable antiferromagnetism. Classical Monte Carlo simulations based on exchange interactions inferred from [Formula: see text]-oriented high-field spin wave measurements confirm that antiferromagnetism is metastable within the otherwise ferromagnetic ground state. The apparent lack of coherent spin wave excitations and strong sensitivity to quenched disorder characterizing [Formula: see text] is a consequence of this multiphase magnetism.
我们利用中子散射表明，在烧绿石量子磁体[化学式：见原文]的低温状态下，铁磁性和反铁磁性共存。虽然磁性布拉格峰证明了长程静态铁磁序，但非弹性散射表明也存在短程关联反铁磁性。小角中子散射为我们与亚稳态反铁磁性相关联的中尺度磁结构提供了直接证据。基于从[化学式：见原文]取向的高场自旋波测量推断出的交换相互作用进行的经典蒙特卡罗模拟证实，反铁磁性在其他方面为铁磁基态内是亚稳态的。[化学式：见原文]所具有的明显缺乏相干自旋波激发以及对淬火无序的强敏感性是这种多相磁性的结果。
