Uniaxial-stress induced magnetic order in CeNiSn

We report the observation of an unexpected magnetic transition in the Kondo semimetal CeNiSn under uniaxial pressures. For $P\parallel a,$ both the specific heat C and magnetic susceptibility χ decrease steadily with increasing P. By contrast, once $P\parallel b$ and $P\parallel c$ exceed 0.13 GPa, $C\left(T\right)\mathrm{}$ exhibits a distinct jump at 4 K followed by a peak at 3 K. The concomitant peaking in $\chi \mathrm{}\left(T\right)\mathrm{}$ for $P\parallel B\parallel c$ is indicative of an antiferromagnetic transition.