Vortex melting line and dimensional crossover in Ba2Can-1CunO2n(O1-y,Fy)2 cuprate superconductors
Vortex melting line and dimensional crossover in Ba2Can-1CunO2n(O1-y,Fy)2 cuprate superconductors
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DOI：
10.1016/j.physc.2007.11.041
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发表时间：
2008-04-01
影响因子：
1.7
通讯作者：
Hamada, N.
中科院分区：
文献类型：
--
作者：
Shivagan, D. D.;Shirage, P. M.;Hamada, N.
Ba_2Can-1CunO_2n（O_1-y，F-y）（2）[F（2 y）-0_2（n-1）n]，顶端氧位F-取代的同系化合物，具有较薄的7.4埃电荷储存层（CRL），在这些体系中预期有较强的层间涡旋耦合。我们测量了高压合成的Ba_2Ca_3Cu_4O_8（O_1-yF_y）（2）的涡旋熔化线（2 y = 2.0）具有CuO 2层和Ba 2Ca 1Cu 2 O 4（O 1-yFy）的2个内平面（IP）的多层系统（2）（2 y = 1.4，1.6和2.0）无IP的双层体系;使用基波和三次谐波磁化率响应，在非常低的交流场幅度和高达12 T的直流场下对优先取向的微晶进行。这些实验熔化线是由公认的双流体模型理论描述的。我们在重度欠掺杂的F（2.0）-0212样品中观察到3D到2D的交叉，而在F（2.0）-0234样品中这种涡旋晶格交叉不明显;并根据重度欠掺杂和自掺杂状态进行解释。(C)2008 Elsevier B. V.保留所有权利。
Ba2Can-1CunO2n(O1-y,F-y)(2)[F(2y)-02(n-1)n], homologous series with F-substitution at apical oxygen site possess a thinner, 7.4 angstrom, charge reservoir layer (CRL) and a strong interlayer vortex coupling was expected in these systems. We measured the vortex melting lines of high pressure synthesized Ba2Ca3Cu4O8(O1-yFy)(2) (2y = 2.0) multilayered system with 2 inner planes (IP) Of CUO2 layers and Ba2Ca1Cu2O4(O1-yFy)(2) (2y = 1.4, 1.6 and 2.0) bilayer system with no IP; using fundamental and third harmonic susceptibility response carried out onto preferentially oriented crystallites at very low ac field amplitude and applied dc fields up to 12 T. These experimental melting lines are described by the commonly accepted theory of two-fluid model. We observed 3D to 2D crossover in heavily underdoped F(2.0)-0212 sample, whereas such a vortex lattice crossover is not evident in F(2.0)-0234 sample; and explained on the basis of heavily underdoped and self doped states. (C) 2008 Elsevier B.V. All rights reserved.