Magnetic-field-induced enhancement of the vortex pinning in the overdoped regime of La$_{2-x}$Sr$_x$CuO$_4$ : Relation to the microscopic phase separation
Magnetic-field-induced enhancement of the vortex pinning in the overdoped regime of La$_{2-x}$Sr$_x$CuO$_4$ : Relation to the microscopic phase separation
复制标题
La$_{2-x}$Sr$_x$CuO$_4$ 过掺杂区域中磁场诱导的涡旋钉扎增强：与微观相分离的关系
DOI：
10.1143/jpsj.76.113706
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Y. Koike
中科院分区：
文献类型：
--
作者：
Y. Tanabe;T. Adachi;K. Omori;Hidetaka Sato;T. Noji;Y. Koike
为了研究过掺杂高Tc铜氧化物超导态的不均匀性，我们测量了La 2-x SrxCuO 4（LSCO）单晶在过掺杂状态下，在平行于c轴的磁场中，零场冷却后升温至7 T，测量了超导态的磁化率。已经发现，对于$x$ = 0.198和0.219，$\chi$在1 T中的温度依赖性显示出平台，即，$\chi$在SC状态中的中等温度范围内几乎与温度无关。此外，在这些晶体中明显地出现了磁化曲线中的所谓第二峰。这些结果表明异常增强的涡旋钉扎，并强烈建议发生$微观$相分离到SC和正常状态的区域中过掺杂的高$T_{\rmc}$铜酸盐。
In order to investigate the inhomogeneity of the superconducting (SC) state in the overdoped high-$T_{\rm c}$ cuprates, we have measured the magnetic susceptibility, $\chi$, of La$_{2-x}$Sr$_x$CuO$_4$ (LSCO) single crystals in the overdoped regime in magnetic fields parallel to the c-axis up to 7 T on warming after zero-field cooling. It has been found for $x$ = 0.198 and 0.219 that the temperature dependence of $\chi$ in 1 T shows a plateau, that is, $\chi$ is almost independent of temperature in a moderate temperature-range in the SC state. Moreover, a so-called second peak in the magnetization curve has markedly appeared in these crystals. These results indicate an anomalous enhancement of the vortex pinning and strongly suggest the occurrence of a $microscopic$ phase separation into SC and normal-state regions in the overdoped high-$T_{\rm c}$ cuprates.