Superconductivity of Lanthanum Superhydride Investigated Using the Standard Four-Probe Configuration under High Pressures

Recently,the theoretically predicted lanthanum superhydride,LaH_10±δ,with a clathrate-like structure was successfully synthesized and found to exhibit a record high superconducting transition temperature T_c≈250 K at～170 GPa,opening a new route for room-temperature superconductivity.However,since in situ experiments at megabar pressures are very challenging,few groups have reported the ～250 K superconducting transition in LaH_10±δ.Here,we establish a simpler sample-...     

一种实时测量大尺寸REBCO超导块材三维空间磁场及温度分布的装置北大核心CSCD

由于单畴RE-Ba-Cu-O(简称REBCO,其中RE为稀土元素:Nd,Y,Gd,Sm)超导块材具有较高的捕获磁场和较大磁悬浮力等优良的特点,使得其在超导磁悬浮,超导磁体,储能飞轮等高新技术领域有着广泛的应用前景.然而,REBCO超导块材捕获磁场的高低,不仅与其自身特性有关,还与其磁化的方式有关,即与样品在不同条件下的磁化机制密切相关.为了更好的研究高温超导体在不同条件下的磁化机制和磁化规律,进一步提高REBCO超导块材的捕获磁场强度,我们自主设计并制作了一种可实时测量大尺寸REBCO超导块材三维空间磁场及样品表面温度分布的装置.在液氮温度(77K)下,通过对磁化过程中圆柱状单畴GdBCO超导块材表面中心由内到外不同位置处磁场的测量,获得了样品的三维磁场强度随外加磁场实时变化的动态曲线图,揭示了随外加磁场的变化,GdBCO超导块材体内磁场由外向内逐渐扩散和运动、由内向外逐渐扩散和逃逸的机制,同时,对样品中存在的磁通蠕动规律进行了分析.此外,本装置还可用于对其它设备(如电机等)的动态磁场和温度进行实时测量.     

Emergence of Superconductivity on the Border of Antiferromagnetic Order in RbMn6Bi5 under High Pressure:A New Family of Mn-Based Superconductors

We report the discovery of superconductivity on the border of antiferromagnetic order in a quasi-one-dimensional material RbMn₆Bi₅ via measurements of resistivity and magnetic susceptibility under high pressures.Its phase diagram of temperature versus pressure resembles those of many magnetism-mediated superconducting systems.With increasing pressure,its antiferromagnetic ordering transition with T_N=83 K at ambient pressure is first enhanced moderately and then s...     

BaO掺杂对单畴GdBCO超导块材性能的影响(二)

为了有效地抑制Gd BCO超导块材在生长过程中出现的Gd/Ba替换现象,在前期工作的基础上,本文采用顶部籽晶熔渗生长工艺,通过在固相先驱粉中添加不同含量的Ba O粒子成功地制备出了一系列高性能的单畴Gd BCO超导块材,并且对样品的微观形貌以及临界电流密度进行了研究和分析.结果表明,随着BaO掺杂量的增加,样品中的Gd_(1+x)Ba_(2-x)Cu_3O_(7-δ)固溶体(Gd123ss)相呈现出减少的趋势,并生成了纳米量级的Gd123ss,这对GdBCO超导样品中存在的Gd/Ba替换起到了很好的抑制作用,使得样品中的GdBa_2Cu_3O_(7-δ)(Gd123)超导相有所增加;同时当样品中BaO的添加量在2 wt%—4 wt%之间时,样品的临界电流密度在一定程度上得到了有效提高.     

Emergence of High-Temperature Superconducting Phase in Pressurized La3Ni2O7 Crystals

The recent report of pressure-induced structural transition and signature of superconductivity with T_c≈80 K above 14 GPa in La₃Ni₂O₇ crystals has garnered considerable attention.To further elaborate this discovery,we carried out comprehensive resistance measurements on La₃Ni₂O₇ crystals grown in an optical-image floating zone furnace under oxygen pressure(15 bar) using a diamond anvil cell(DAC) and cubic anvil cell(CAC)...