Spin reorientation in the square-lattice antiferromagnets RMnAsO (R = Ce, Nd): density functional analysis of the spin-exchange interactions between the rare-earth and transition-metal ions.
Spin reorientation in the square-lattice antiferromagnets RMnAsO (R = Ce, Nd): density functional analysis of the spin-exchange interactions between the rare-earth and transition-metal ions.
复制标题
方晶格反铁磁体 RMnAsO (R = Ce, Nd) 中的自旋重定向：稀土离子和过渡金属离子之间自旋交换相互作用的密度泛函分析。
作者：
Changhoon Lee;E. Kan;H. Xiang;R. Kremer;Seung;Z. Hiroi;M. Whangbo
用密度泛函方法分析了稀土与过渡金属离子(R(3+)和Mn(2+))之间的自旋交换作用，研究了正方晶格反铁磁体RMnAsO(R=Ce，ND)的自旋重取向(SR)现象。结果表明，Dzyaloshinskii-Moriya(DM)相互作用的对称性和强度主要由R(3+)离子的4f态决定，R(3+)和Mn(2+)离子之间的Dzyaloshinskii-Moriya(DM)和双二次(BQ)交换异常强烈，控制着观察到的自旋重取向现象.在其SR温度以下，CeMnAsO中的Mn(2+)和Ce(3+)磁矩是正交的，而在NdMnAsO中是共线的，这是因为在CeMnAsO中DM相互作用占主导地位，而在NdMnAsO中则相反。为检验我们的发现的含义而设计的实验也被提出。
The spin reorientation (SR) phenomenon of the square-lattice antiferromagnets RMnAsO (R = Ce, Nd) was investigated by analyzing the spin-exchange interactions between the rare-earth and the transition-metal ions (R(3+) and Mn(2+), respectively) on the basis of density functional calculations. It is found that the symmetry and strength of the Dzyaloshinskii-Moriya (DM) interaction are determined primarily by the partially filled 4f states of the R(3+) ions and that the DM and biquadratic (BQ) exchanges between the R(3+) and the Mn(2+) ions are unusually strong and control the observed spin reorientation phenomenon. Below their SR temperature, the Mn(2+) and Ce(3+) moments are orthogonal in CeMnAsO but are collinear in NdMnAsO, because the DM interaction dominates over the BQ interaction for CeMnAsO, while the opposite is the case for NdMnAsO. Experiments designed to test the implications of our findings are proposed.