Exploring Low-Temperature Magnetism in a Novel Rare-Earth Trihalide.

Rare-earth trihalides have recently gained attention as promising systems for studying quantum magnetism, where strong spin-orbit coupling and crystal-field effects can lead to exotic magnetic ground states such as quantum spin liquids (QSLs). In this work, we investigate the low-temperature magnetic properties of a new 4f rare-earth trihalide using DC magnetization and AC susceptibility measurements. The material shows a clear magnetic ordering transition near 0.2K with a critical field around 0.2 T. Frequency-dependent AC measurements rule out spin-glass behavior, confirming the presence of long-range magnetic order. Interestingly, an additional field-induced magnetic phase emerges near 0.3T. These results indicate field-tunable magnetic correlations and suggest that this rare-earth trihalide is a promising canddate for exploring exotic magnetic phases.