Superconducting properties of iron-containing ternary silicides Lu-Fe-Si

含铁三元硅化物Lu-Fe-Si的超导性能

基本信息

批准号：
61540231
负责人：
OOTA Akio
金额：
$ 1.22万
依托单位：
Toyohashi University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

Superconductivity has been studied through electrical resistivity, Hall coefficient and AC susceptibility on a series of iron-containing rare earth silicides Lu-Fe-Si around the stoichiometric composition Lu_2Fe_3Si_5. The superconducting transition temperature T_c shows a maximum (-6.0K) on the stoichiometry and decreases with a deviation from itespecially on the Fe-rich side. The upper critical field for Lu_2Fe_3Si_5 increases linearly with decreasing temperature with a slope of about 1.5 Tesla/K, which is nearly the same as the ones for other off-stoichiometic samples in spite of the difference in T_2. All samples show a monotonic increase in resistivity with temperature in the range between T_c and 300K. The resistivity ratio <vho>(300K)/<rho>(6K) equals to -16 for Lu_2Fe_3Si_5 and decreases with a deviation from the stoichiometry especially on the Fe-rich side, which indicates the appearance of disorder in the sample as expected from the result of T_c. All samples show T^2 dependence of resistivity at lowtemperatures, which is interpreted in terms of electron-electron scattering. The carrier concentration of Lu_2Fe_3 obtained from Hall coefficiet is independent of temperature between T_c ad 300K, and is estimated to be 6 x 10^<27> m^<-3>, which is compared with 1 x 10^<27> m^<-3> for another isostructural sample Y_2Fe_3Si_5 with T_c = 2.4K. The difference in T_c between them would be ascribed to the difference of carrier concentration.

通过电阻率、霍尔系数和交流磁化率研究了化学计量组成Lu_2Fe_3Si_5周围的一系列含铁稀土硅化物Lu-Fe-Si的超导性。超导转变温度T_c在化学计量上显示出最大值（-6.0K），并且随着偏离化学计量而降低，特别是在富铁侧。 Lu_2Fe_3Si_5的上临界场随着温度的降低呈线性增加，斜率约为1.5 Tesla/K，尽管T_2存在差异，但与其他非化学计量样品的上临界场几乎相同。在 T_c 和 300K 范围内，所有样品的电阻率均随温度单调增加。对于 Lu_2Fe_3Si_5，电阻率比 <vho>(300K)/<rho>(6K) 等于 -16，并且随着与化学计量的偏差而减小，特别是在富 Fe 一侧，这表明样品中出现了无序，正如预期的那样T_c 的结果。所有样品都显示出低温下电阻率与 T^2 的相关性，这可以用电子-电子散射来解释。由霍尔系数得到的Lu_2Fe_3载流子浓度在T_c至300K之间与温度无关，估计为6 x 10^<27> m^<-3>，与1 x 10^<27> m^进行比较<-3> 另一个同构样品 Y_2Fe_3Si_5，T_c = 2.4K。它们之间的 T_c 差异可归因于载流子浓度的差异。