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

## TL;DR

This study investigates the magnetic ground state of antiperovskite Cr$_3$GeN, revealing it to be Pauli paramagnetic with no long-range magnetic order, through $^{14}$N-NMR and $$SR measurements.

## Contribution

The paper provides the first detailed magnetic characterization of Cr$_3$GeN, demonstrating its paramagnetic ground state using advanced NMR and muon spin relaxation techniques.

## Key findings

- Cr$_3$GeN is magnetically inactive at low temperatures.
- The ground state is Pauli paramagnetic, lacking antiferromagnetic order.
- Structural transition occurs with large hysteresis at 300--400 K.

## Abstract

The antiperovskite-related nitride Cr$_3$GeN forms a tetragonal structure with the space group $P\bar{4}2_1m$ at room temperature. It shows a tetragonal ($P\bar{4}2_1m$) 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 $\mu$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.