Effect of Nonmagnetic Ion Lu Substitution for Dy on Superconductivity and Magnetism in Antiferromagnetic Superconductor Dy1-xLuxNi2B2C Compound

概要

論文の詳細を見る
A series of Dy1-xLuxNi2B2C ($x=0--1$) compounds have been investigated by X-ray diffraction and by examining the temperature dependences of electrical resistivity, magnetization and heat capacity. All the samples exhibit the same LuNi2B2C-type structure; and lattice parameters depend almost linearly on the Lu concentration $x$. The superconducting transition temperature $T_{\text{c}}$ decreases rapidly with increasing $x$, and superconductivity disappears at approximately $x=0.2$, then increases with a further increase in $x$. The magnetic transition temperature $T_{\text{M}}$ and the effective magnetic moment $P_{\text{eff}}$ decrease gradually with increasing $x$. The ferrimagnetic-like behavior emerges at about $x=0.2$; which can be the main reason causing the suppression of superconductivity. The temperature dependence of the magnetic entropy $S_{\text{m}}$ originated from Dy ions has been evaluated on the basis of heat capacity data. The saturated values of $S_{\text{m}}(T)/(1-x)$ are approximately 90% of $R\ln 4$ and the effective magnetic moment normalized by Dy concentration is almost unchanged, which indicates that the magnetic ground state of Dy3+ does not show a pronounced change.
2007-10-15