Magnetic Properties under Pressure in Novel Spin-Triplet Superconductor UTe2

TL;DR

This study investigates how pressure influences magnetic properties in the novel spin-triplet superconductor UTe2, revealing changes in magnetic anisotropy and detecting magnetic anomalies suggestive of complex magnetic interactions.

Contribution

It provides new insights into pressure-induced magnetic behavior and anomalies in UTe2, highlighting the interplay of various magnetic fluctuations and phases.

Findings

Suppression of magnetic susceptibility along the a-axis under pressure.

Detection of magnetic anomalies at T_MO and T_WMO above critical pressure.

Evidence of complex magnetic interactions involving multiple fluctuations.

Abstract

We report the magnetic susceptibility and the magnetization under pressures up to 1.7GPa above the critical pressure, Pc ~ 1.5GPa, for H // a, b, c-axes in the novel spin triplet superconductor UTe2. The anisotropic magnetic susceptibility at low pressure with the easy magnetization a-axis changes to the quasi-isotropic behavior at high pressure, revealing a rapid suppression of the susceptibility for a-axis, and a gradual increase of the susceptibility for the b-axis. At 1.7GPa above Pc, magnetic anomalies are detected at T_MO ~ 3K and T_WMO ~ 10K. The former anomaly corresponds to long-range magnetic order, most likely antiferromagnetism, while the latter shows a broad anomaly, which is probably due to the development of short range order. The unusual decrease and increase of the susceptibility below T_WMO for H // a and b-axes, respectively, indicate the complex magnetic properties at low temperatures above Pc. This is related to the interplay between multiple fluctuations dominated by antiferromagnetism, ferroamgnetism, valence and Fermi surface instabilities.