Elastic Instabilities within Antiferromagnetically Ordered Phase in the Orbitally-Frustrated Spinel GeCo_2O_4
Elastic Instabilities within Antiferromagnetically Ordered Phase in the Orbitally-Frustrated Spinel GeCo_2O_4
复制标题
轨道受阻尖晶石 GeCo_2O_4 中反铁磁有序相内的弹性不稳定性
DOI：
10.1103/physrevb.84.020409
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
T.Watanabe
中科院分区：
文献类型：
--
作者：
正木伸尚;北之園拓;小林修;T.Watanabe
轨道受挫的尖晶石GeCoO的超声速度测量揭示了反铁磁相中独特的弹性反常。在反铁磁相区，剪切模数与温度的依赖关系最小，这表明剪切声子与分子自旋轨道激发的耦合。弹性模随磁场的变化呈现出双重反常，可解释为磁场诱导的超磁相变和结构相变。这些弹性反常现象表明，几何受挫的存留，以及自旋、轨道和晶格自由度的相互作用，在反铁磁相中引发了一系列现象。
Ultrasound velocity measurements of the orbitally frustrated spinel GeCoOreveal unique elastic anomalies within the antiferromagnetic phase. Temperature dependence of shear moduli exhibits a minimum within the antiferromagnetic phase, suggesting the coupling of shear acoustic phonons to molecular spin-orbit excitations. Magnetic-field dependence of elastic moduli exhibits diplike anomalies, being interpreted as magnetic-field-induced metamagnetic and structural transitions. These elastic anomalies suggest that the survival of geometrical frustration, and the interplay of spin, orbital, and lattice degrees of freedom evoke a set of phenomena in the antiferromagnetic phase.