Orbital order and ferrimagnetic properties of Sr8CaRe3Cu4O24.
Orbital order and ferrimagnetic properties of Sr8CaRe3Cu4O24.
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DOI：
10.1103/physrevlett.94.087205
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发表时间：
2004-05
影响因子：
8.6
通讯作者：
X. Wan;M. Kohno;X. Hu
中科院分区：
文献类型：
--
作者：
X. Wan;M. Kohno;X. Hu
采用LSDA+U（局域自旋密度近似加Hubbard U）方法和绿色函数方法，研究了新材料Sr 8 CaRe 3Cu 4 O 24的电子和磁性。我们的LSDA+U计算表明，该系统是亚铁磁性的绝缘体，其净磁矩为1.01微（B）/f.u.，这与实验结果吻合得很好。正是由于Re原子的存在，使得Cu原子的d电子轨道有序化，从而导致了Cu原子间强的交换作用和高的磁转变温度。基于LSDA+U的结果，我们引入了一个有效的自旋自由度模型，并利用绿色函数方法研究了其有限温度性质。所得结果与实验结果一致，表明自旋交替海森堡模型适用于该化合物。
By means of the LSDA+U (local spin density approximation plus Hubbard U) method and the Green function method, we investigate the electronic and magnetic properties of the new material of Sr8CaRe3Cu4O24. Our LSDA+U calculation shows that this system is an insulator of ferrimagnetism with a net magnetic moment of 1.01 micro(B)/f.u., which is in good agreement with the experiment. It is the nonmagnetic Re atoms that induce an orbital order of d electrons of Cu atoms, which is responsible for the strong exchange interaction and the high magnetic transition temperature. Based on the LSDA+U results, we introduce an effective model for the spin degrees of freedom and investigate the finite-temperature properties by the Green function method. The obtained results are consistent with the experimental results, indicating that the spin-alternating Heisenberg model is suitable for this compound.