Unusual Kondo-hole effect and crystal-field frustration in Nd-doped CeRhIn${}_5$

Abstract

We investigate single crystalline samples of Ce${}_{1-x}$Nd${}_x$RhIn${}_5$ by means of X-ray diffraction, microprobe, magnetic susceptibility, heat capacity, and electrical resistivity measurements. Our data reveal that the antiferromagnetic transition temperature of CeRhIn${}_5$, $T_N^{\mathrm{Ce}}=3.8$ K, is linearly suppressed with $x_{\mathrm{Nd}}$, by virtue of the "Kondo hole" created by Nd substitution. The extrapolation of $T_N^{\mathrm{Ce}}$ to zero temperature, however, occurs at $x_c\sim 0.3$, which is below the 2D percolation limit found in Ce${}_{1-x}$La${}_x$RhIn${}_5$. This result strongly suggests the presence of crystal-field frustration effects. Near $x_{\mathrm{Nd}}\sim 0.2$, the Ising AFM order from Nd ions is stabilized and $T_N^{\mathrm{Nd}}$ increases up to $11$ K in pure NdRhIn${}_5$. Our results shed light on the effects of magnetic doping in heavy-fermion antiferromagnets and stimulate the study of such systems under applied pressure.

6 pages, 6 figures