Paramagnetic-to-nonmagnetic transition in antiperovskite nitride Cr${}_3$GeN studied by ${}^{14}$N-NMR and $\hat{I}¼$SR

Abstract

The antiperovskite-related nitride Cr${}_3$GeN forms a tetragonal structure with the space group $P\bar{4}{2}_{1}m$ at room temperature. It shows a tetragonal ($P\bar{4}{2}_{1}m$) to tetragonal ($I4/mcm$) structural transition with a large hysteresis at 300--400 K. The magnetic susceptibility of Cr${}_3$GeN shows Curie-Weiss type temperature dependence at high temperature, but is almost temperature-independent below room temperature. We carried out $\hat{I}¼$SR and ${}^{14}$N-NMR microscopy measurements to reveal the magnetic ground state of Cr${}_3$GeN. Gradual muon spin relaxation, which is nearly temperature-independent below room temperature, was observed, indicating that Cr${}_3$GeN is magnetically inactive. In the ${}^{14}$N-NMR measurement, a quadrupole-split spectrum was obtained at around ${}^{14}K=0$. The temperature dependence of ${}^{14}(1/T_1)$ satisfies the Korringa relation. These experimental results indicate that the ground state of Cr${}_3$GeN is Pauli paramagnetic, without antiferromagnetic long-range order.

4 pages, 4 figures, proceeding of International Workshop on Itinerant-Electron Magnetism to be appeared in J. Phys. Conf. Ser