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High quality single crystal CaFe4As3 was grown by using the Sn flux method. Unlike layered CaFe2As2, CaFe4As3 crystallizes in an orthorhombic three-dimensional structure. Two magnetic ordering transitions are observed at ~90 K and ~27 K, respectively. The high temperature transition is an antiferromagnetic(AF) ordering transition. However, the low temperature transition shows complex properties. It shows a ferromagnetic-like transition when a field is applied along b-axis, while antiferromagnetism-like transition when a field is applied perpendicular to b-axis. These results suggest that the low temperature transition at 27 K is a first-order transition from an AF state to a canted AF state. In addition, the low temperature electron specific heat coefficient reaches as high as 143 mJ/mol·K2, showing a heavy fermion behavior. 相似文献
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论述了陶瓷器型几何设计的关键问题,着重讨论了一种基于二次贝塞尔曲线的陶瓷器型表面上的曲线设计方法.为了克服单段二次贝塞尔曲线不足,探讨了双段二次贝塞尔曲线的求解设计方法,并通过一个实例验证了该方法的有效性. 相似文献
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研究了用自组装法制备的质子酸掺杂的纳米管结构聚苯胺的电阻率(ρ)和磁化率随温度变化的依赖关系,讨论了质子酸掺杂浓度、不同对阴离子以及苯胺单体与质子酸聚合时反应浓度对纳米管结构聚苯胺电学性质的影响.实验结果表明,lnρ和T-1/2呈线性关系,不同对阴离子对聚苯胺的电阻率影响很大,随着质子酸掺杂浓度以及苯胺单体与质子酸聚合时反应浓度的增大,聚苯胺的电阻率明显减小;而且,其磁化率可以表示为与温度无关的泡利顺磁性和符合居里定律的顺磁性之和. 相似文献