Structural transition and orbital glass physics in near-itinerant CoV2O4
Structural transition and orbital glass physics in near-itinerant CoV2O4
复制标题
近流动 CoV2O4 的结构转变和轨道玻璃物理
DOI：
10.1103/physrevb.93.014437
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发表时间：
2015
影响因子：
3.7
通讯作者：
Gregory MacDougall
中科院分区：
文献类型：
--
作者：
D. Reig;D. Casavant;V. Garlea;A. Aczel;Mikhail Feygenson;J. Neuefeind;H. D. Zhou;H. D. Zhou;S. Nagler;S. Nagler;Gregory MacDougall
在这项研究中，亚铁磁性尖晶石CoV 2 O 4一直是一个热门的话题，最近的兴趣，无论是作为一个挫折的绝缘体与未淬灭的轨道简并和作为一个近巡回磁铁，可以驱动金属与适度的压力。在这里，我们报告我们最近的中子衍射和非弹性散射测量粉末与最小的阳离子位点的障碍。我们的主要新结果是在T ~* = 90 K处发现了一个弱的（Δa/a ~ 10-4）一级结构相变，在最近的单晶测量中发现了自旋倾斜。这种转变的特点是由氧八面体位置的短程畸变，和非弹性数据进一步建立一个弱的1.25meV的自旋能隙在低温下。总之，这些研究结果提供了强有力的支持本地轨道图片和存在的轨道玻璃态温度低于T*。
In this study, the ferrimagnetic spinel CoV2O4 has been a topic of intense recent interest, both as a frustrated insulator with unquenched orbital degeneracy and as a near-itinerant magnet which can be driven metallic with moderate applied pressure. Here, we report on our recent neutron di raction and inelastic scattering measurements on powders with minimal cation site disorder. Our main new result is the identification of a weak (Δa/a ~ 10–4), first order structural phase transition at T* = 90 K, the same temperature where spin canting was seen in recent single crystal measurements. This transition is characterized by a short-range distortion of oxygen octahedral positions, and inelastic data further establish a weak 1.25meV spin gap at low temperature. Together, these findings provide strong support for the local orbital picture and the existence of an orbital glass state at temperatures below T*.