Measurements of the NMR Knight shift tensor and nonlinear magnetization in URu$_2$Si$_2$

TL;DR

This study investigates the nonlinear magnetic properties of URu$_2$Si$_2$, revealing a smaller nonlinear magnetization than previously reported and suggesting sample dependence of the anomalous peak in the hidden order transition.

Contribution

It provides direct magnetization measurements and detailed angular dependence of the $^{29}$Si NMR Knight shift tensor in URu$_2$Si$_2$, highlighting the sample-dependent nature of the anomaly.

Findings

Nonlinear magnetization is smaller than previously reported.

The nonlinear Knight shift tensor is below detection limit.

The anomalous peak's magnitude varies with sample.

Abstract

URu$_2$Si$_2$ exhibits an anomalous peak in the nonlinear magnetic susceptibility at the hidden order transition. In order to investigate this anomaly, we conducted direct magnetization measurements and investigated the detailed angular dependence of the $^{29}$Si nuclear magnetic resonance Knight shift tensor. We find that the nonlinear magnetization is smaller than previously reported, and the analogous nonlinear Knight shift tensor is below the detection limit. Our results suggest that the magnitude of the anomalous peak is sample dependent.