Sim Hasung, Oh Joosung, Jeong Jaehong, Le Manh Duc, Park Je Geun
Center for Correlated Electron Systems, Institute for Basic Science (IBS) and Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea.
Acta Crystallogr B Struct Sci Cryst Eng Mater. 2016 Feb;72(Pt 1):3-19. doi: 10.1107/S2052520615022106. Epub 2016 Jan 23.
The hexagonal RMnO3(h-RMnO3) are multiferroic materials, which exhibit the coexistence of a magnetic order and ferroelectricity. Their distinction is in their geometry that both results in an unusual mechanism to break inversion symmetry and also produces a two-dimensional triangular lattice of Mn spins, which is subject to geometrical magnetic frustration due to the antiferromagnetic interactions between nearest-neighbor Mn ions. This unique combination makes the h-RMnO3 a model system to test ideas of spin-lattice coupling, particularly when both the improper ferroelectricity and the Mn trimerization that appears to determine the symmetry of the magnetic structure arise from the same structure distortion. In this review we demonstrate how the use of both neutron and X-ray diffraction and inelastic neutron scattering techniques have been essential to paint this comprehensive and coherent picture of h-RMnO3.
六方相RMnO3（h-RMnO3）是多铁性材料，表现出磁有序和铁电性的共存。它们的独特之处在于其几何结构，这既导致了一种打破反演对称性的异常机制，又产生了一个二维的Mn自旋三角晶格，由于最近邻Mn离子之间的反铁磁相互作用，该晶格受到几何磁阻挫的影响。这种独特的组合使h-RMnO3成为测试自旋-晶格耦合概念的模型系统，特别是当非本征铁电性和似乎决定磁结构对称性的Mn三聚化都源于相同的结构畸变时。在这篇综述中，我们展示了如何使用中子和X射线衍射以及非弹性中子散射技术来描绘h-RMnO3这幅全面且连贯的图像。
