Noncollinear antiferromagnetism of coupled spins and pseudospins in the double perovskite La2CuIrO6
Noncollinear antiferromagnetism of coupled spins and pseudospins in the double perovskite La2CuIrO6
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DOI：
10.1103/physrevb.94.144437
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发表时间：
2016-08
影响因子：
3.7
通讯作者：
K. Manna;R. Sarkar;S. Fuchs;Y. Onykiienko;A. Bera;G. A. Cansever;S. Kamusella;A. Maljuk;C. Blum
中科院分区：
文献类型：
--
作者：
K. Manna;R. Sarkar;S. Fuchs;Y. Onykiienko;A. Bera;G. A. Cansever;S. Kamusella;A. Maljuk;C. Blum
本文报道了双钙钛矿化合物{{mathm{La}}_2}{\mathm{CuIrO}}_{6}的结构、磁学和热力学性质，从X射线、中子衍射、中子退极化、磁化强度、磁化率、比热、介子自旋弛豫、电子自旋共振(ESR)和核磁共振(核磁共振)等方面进行了研究。在113$K以下，短程自旋-自旋关联发生在次晶格中。随着温度的降低，亚晶格逐渐参与到关联过程中。在$T=74$K以下，Cu(自旋$\mathit{S}=\crc{1}{2}$)和Ir(伪自旋$\mathit{j}=\crc{1}{2}$)中的磁亚晶格是强耦合的，并表现出反铁磁相变到非共线磁性结构，并伴随着一个小的未补偿的横矩。在54K时，磁化率、核磁共振和自旋晶格驰豫速率的弱反常被解释为受强自旋轨道耦合的离子{4+}影响的横向力矩的协同有序.我们认为，在{{mathm{La}}_{2}{\mathm{CuIrO}}_{6}中观察到的丰富的磁性行为与强关联的只有自旋的{d}离子和强自旋轨道耦合的{5\mathit{d}$过渡离子之间的复杂磁相互作用有关，其中自旋轨道耦合和晶格的低对称性的结合对磁有序状态下的自旋结构起着特殊的作用。
We report the structural, magnetic, and thermodynamic properties of the double perovskite compound ${\mathrm{La}}_{2}{\mathrm{CuIrO}}_{6}$ from x-ray, neutron diffraction, neutron depolarization, $\mathit{dc}$ magnetization, $\mathit{ac}$ susceptibility, specific heat, muon-spin-relaxation $(\ensuremath{\mu}\mathrm{SR})$, electron-spin-resonance (ESR) and nuclear magnetic resonance (NMR) measurements. Below $\ensuremath{\sim}113$ K, short-range spin-spin correlations occur within the ${\mathrm{Cu}}^{2+}$ sublattice. With decreasing temperature, the ${\mathrm{Ir}}^{4+}$ sublattice is progressively involved in the correlation process. Below $T=74$ K, the magnetic sublattices of Cu (spin $\mathit{s}=\frac{1}{2}$) and Ir (pseudospin $\mathit{j}=\frac{1}{2}$) in ${\mathrm{La}}_{2}{\mathrm{CuIrO}}_{6}$ are strongly coupled and exhibit an antiferromagnetic phase transition into a noncollinear magnetic structure accompanied by a small uncompensated transverse moment. A weak anomaly in $\mathit{ac}$ susceptibility as well as in the NMR and $\ensuremath{\mu}\mathrm{SR}$ spin lattice relaxation rates at 54 K is interpreted as a cooperative ordering of the transverse moments which is influenced by the strong spin-orbit coupled $5\mathit{d}$ ion ${\mathrm{Ir}}^{4+}$. We argue that the rich magnetic behavior observed in ${\mathrm{La}}_{2}{\mathrm{CuIrO}}_{6}$ is related to complex magnetic interactions between the strongly correlated spin-only $3\mathit{d}$ ions with the strongly spin-orbit coupled $5\mathit{d}$ transition ions where a combination of the spin-orbit coupling and the low symmetry of the crystal lattice plays a special role for the spin structure in the magnetically ordered state.