Magnetocaloric effect and critical behavior in a periodic Anderson-like organic polymer

来源 :湖北省物理学会、武汉物理学会2015学术年会 | 被引量 : 0次 | 上传用户:sunfeaml
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
We study the magnetocaloric effect and critical behavior of a periodic Anderson-like organic polymer using Greens function theory, in which the localized f orbitals hybridize with the conduction orbitals at even sites.The field-induced metal-insulator transitions with the magnetic Grüneisen parameter showing 丨(T)h丨~T1 power-law critical behaviour are revealed, which provides a new thermodynamic means for probing quantum phase transitions.It is found that the competition of up-spin and down-spin hole excitations is responsible for the double peak structure of magnetic entropy change(-ΔS) for the dominant Kondo coupling case, implying a double magnetic cooling process via demagnetization, which follows a power law dependence of magnetic field h:-ΔS~hn.The local exponent n tends to 1 and 2 below and above Tc, while has a minimum 0.648 at Tc, which is close to-ΔS~h2/3 for conventional ferromagnets obeying the mean field theory.Δt Tc, the-ΔS~h curves with convex curvature superpose each other for small V values, which are separated by the large V case,distinguishing the RKKY interaction and Kondo coupling explicitly Furthermore, the critical scaling law n(Tc)=1+(β-1)/(β+γ)=1+1/δ(1-1/β) is related to the critical exponents (β, γ, and δ) extracted from the Arrott-Noakes equation of state and Kouvel-Fisher method, which fulfill the Widom scaling relationδ=1+γβ-1, indicating self-consistency and reliability of the obtained results.In addition, based on the scaling hypothesis through checking the scaling analysis of magnetization, the M-T-h curves collapse onto two independent universal branches below and above Tc.
其他文献
处于里德堡态(主量子数远大于1)的原子具有较大的偶极-偶极相互作用,并且可以通过外加电场和磁场调节相互作用的强弱,因此在量子信息处理和量子模拟方面具有重要的应用价值[1
会议
分析了利用近距离引力实验探索洛伦兹不变性破缺效应的现状,并展望了其发展趋势.引力与物质的耦合极其微弱,近距离下牛顿反平方定律的实验检验是探索引力现象对广义相对论偏
会议
在大部分的扭秤实验中,实验的分辨率主要受限于正比于扭秤本征刚性的热噪声.为了获得较高的分辨率本征刚性越小越好,而通常的近距离实验要求刚性越大越好,于是近距离扭秤实验
会议
对于原子干涉仪等精密测量实验来说,低频振动的隔离是十分重要的.为了降低原子干涉仪中的关键器件-拉曼光反射镜的振动噪声,我们设计并实现了一种稳定的超低频主动振动隔离系
会议
Several worldwide projects are in progress to open the gravitational wave (GW) window for observational astronomy.Taken together, these projects will span a wid
会议
环酮类化合物分子结构非常灵活,灵活的结构与该类分子光跃迁选择定则有很密切的关系,另外,该类分子的三重态在其光化学性质及光化学反应中扮演着非常重要的作用,环酮类分子的
会议
在光机械系统中,我们展示一个PT对称破缺的混沌,它的一个特点是需要一个超低驱动阈值.原则上,当一束驱动光打在一个腔膜上并且作用一段时间,混沌就会出现,这个驱动的强度反比
会议
We report the observation of a universal behavior of ultracold quantum critical (QC) Bose gases trapped in a one-dimensional optical lattice.We extract the dens
会议
为了研究细胞在旋转电场下的特性,本文设计一个基于细胞电旋转芯片系统的信号控制器,该信号控制器能向细胞电旋转芯片的电极输出控制信号,使细胞电旋转芯片产生旋转的电场力,
本文以某大型光学谐振腔支撑致稳系统为研究对象,对其动力学特性开展仿真分析和实验研究.首先对部件之间的螺栓联接结构进行研究,分析螺栓预紧力和接触面摩擦系数的影响规律,