He Zheng, Gu Yiqing, Wo Hongliang, Feng Yu, Hu Die, Hao Yiqing, Gu Yimeng, Walker Helen C, Adroja Devashibhai T, Zhao Jun
State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
Shanghai Qi Zhi Institute, Shanghai 200232, China.
Phys Rev Lett. 2021 Oct 1;127(14):147205. doi: 10.1103/PhysRevLett.127.147205.
We report neutron scattering measurements of the spinel oxide LiGaCr_{4}O_{8}, in which magnetic ions Cr^{3+} form a breathing pyrochlore lattice. Our experiments reveal the coexistence of a nearly dispersionless resonance mode and dispersive spin-wave excitations in the magnetically ordered state, which can be quantitatively described by a quantum spin model of hexagonal loops and linear spin-wave theory with the same set of exchange parameters, respectively. Comparison to other Cr spinel oxides reveals a linear relationship between the resonance energy and lattice constant across all these materials, which is in agreement with our hexagonal loop calculations. Our results suggest a unified picture for spin resonances in Cr spinel oxides.
我们报告了对尖晶石氧化物LiGaCr₄O₈的中子散射测量结果，其中磁性离子Cr³⁺形成了呼吸式焦绿石晶格。我们的实验揭示了在磁有序状态下几乎无色散的共振模式和色散自旋波激发的共存，它们分别可以由具有相同交换参数集的六边形环量子自旋模型和线性自旋波理论进行定量描述。与其他Cr尖晶石氧化物的比较表明，在所有这些材料中，共振能量与晶格常数之间存在线性关系，这与我们的六边形环计算结果一致。我们的结果为Cr尖晶石氧化物中的自旋共振提供了一个统一的图景。
