Anomalous vortex melting line in the two-component superconductor (Cu,C)Ba2Ca3Cu4O10+δ
Anomalous vortex melting line in the two-component superconductor (Cu,C)Ba2Ca3Cu4O10+δ
复制标题
DOI：
10.1103/physrevb.74.184517
复制
发表时间：
2006-11-01
影响因子：
3.7
通讯作者：
Watanabe, T.
中科院分区：
文献类型：
--
作者：
Crisan, A.;Tanaka, Y.;Watanabe, T.
利用三次谐波磁化率的共线测量了高压合成的(Cu0.6C0.4)Ba2Ca3Cu4Oy[(Cu，C)：1234]和(Cu0.5C0.5)Ba2Ca2Cu3Oy[(Cu，C)：1223]具有择优取向和不同载流子浓度的晶体的涡旋熔融线。所有的(Cu，C)：1223样品和最佳掺杂的(Cu，C)：1234样品的涡旋熔线都可以用公认的双流体模型中的熔线理论很好地描述。过掺(Cu，C)：1234有一条异常的熔融线，这可以用相当特殊的带隙演化现象来解释，即在低于临界温度的温度下，由于CuO_2外平面的第二个超导带隙的显著打开，其中由于内平面的第一个超导带隙打开。通过假定各向异性因子随温度变化的经验公式，从理论上模拟了过掺(Cu，C)：1234的实验熔线。
Using the on-set of third-harmonic susceptibility we have measured vortex melting lines of high-pressure synthesized (Cu0.6C0.4)Ba2Ca3Cu4Oy [(Cu,C):1234] and (Cu0.5C0.5)Ba2Ca2Cu3Oy [(Cu,C):1223] with preferentially oriented crystallites and having various carrier concentrations. Vortex melting lines of all (Cu,C):1223 samples and of optimum-doped (Cu,C):1234 were very well described by the commonly accepted theory of melting lines within the two-fluid model. Overdoped (Cu,C):1234 proved to have an anomalous melting line, that was phenomenologically explained by the rather special gaps evolution, that is the significant opening of a second superconducting gap due to CuO2 outer planes at a temperature lower than the critical one, where the first superconducting gap due to inner planes opens. The experimental melting lines of overdoped (Cu,C):1234 were modelled theoretically by assuming an empirical formula for the temperature dependence of anisotropy factor.