Matsuda M, Dissanayake S E, Abernathy D L, Qiu Y, Copley J R D, Kumada N, Azuma M
Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
Phys Rev B. 2019;100(13). doi: 10.1103/physrevb.100.134430.
An inelastic neutron scattering study has been performed in an = 3/2 bilayer honeycomb lattice compound BiMnO(NO) at ambient and high magnetic fields. Relatively broad and monotonically dispersive magnetic excitations were observed at ambient field, where no long-range magnetic order exists. In the magnetic-field-induced long-range ordered state at 10 T, the magnetic dispersions become slightly more intense, albeit still broad as in the disordered state, and two excitation gaps, probably originating from an easy-plane magnetic anisotropy and intrabilayer interactions, develop. Analyzing the magnetic dispersions using the linear spin-wave theory, we estimated the intraplane and intrabilayer magnetic interactions, which are almost consistent with those determined by density functional theory calculations [M. Alaei ., Phys. Rev. B , 140404(R) (2017)], except the third and fourth neighbor intrabilayer interactions. Most importantly, as predicted by the theory, there is no significant frustration in the honeycomb plane but frustrating intrabilayer interactions probably give rise to the disordered ground state.
在室温和高磁场下，对一种(\nu = 3/2)双层蜂窝晶格化合物BiMnO(NO)进行了非弹性中子散射研究。在不存在长程磁序的室温磁场下，观察到了相对较宽且单调色散的磁激发。在10 T的磁场诱导长程有序状态下，磁色散变得略微更强，尽管仍如无序状态下一样宽，并且出现了两个激发能隙，可能源于易平面磁各向异性和双层内相互作用。使用线性自旋波理论分析磁色散，我们估计了面内和面内双层磁相互作用，除了第三和第四近邻面内双层相互作用外，这些相互作用与密度泛函理论计算[M. Alaei等人，《物理评论B》，140404(R) (2017)]所确定的几乎一致。最重要的是，正如理论所预测的，蜂窝平面中不存在显著的阻挫，但面内双层相互作用的阻挫可能导致无序基态。
